Life
Life is generally vīta, yes; and as Jack Gallagher wrote, you need for it to be in the accusative: vītam. A poetic alternative might be anima, which though it usually is meaning ‘soul’, also can be understood as ‘life force’ and ‘life’ poetically.
Choose
There are some other options for ‘choose’:
- optō, optāre, optāvī, optātum
- ēligo, ēligere, ēlēgī, ēlēctum
- dēligō, dēligere, dēlēgī, dēlēctum
- sortior, sortīrī, sortītus sum, —
- dēsignō, dēsignāre, dēsignāvī, dēsignātum
- sēligō, sēligere, sēlēgī, sēlēctum
Of these there are four groups:
- optō
- -ligō with the prefixed prepositions ē-, dē-, sē-
- sortior
- -signō with the prefixed preposition dē
optō
The basic meanings of optō include choose, select; wish, wish for, desire. The latter is by Lewis & Short denoted as being ‘the predominant signification of the word; cf.: “volo, cupio, desidero, aveo […]”’. As a noun (optātum) it signifies ‘a wish, desire’ (L&S).
-ligō
The different variants are constructed from lĕgō; the reason it became ligō when conjoined with the prepositions, is because the syllable becomes unstressed because it is short, moving the stress back to the preceding syllable, which causes the vowel to be raised from /e/ to /i/. The basic meaning of lĕgō (as opposed to lēgō) is to bring together, to gather, to collect.
Not surprisingly, this word has gained numerous nuances, such as to take out, remove; to pluck, strip; to wind up, draw together; to ‘take one’s self unjustly’, carry off, steal; poetically: to go, pass, wander through, and hence sail by or coast along the shore; to choose, pick out, single out. Further, it can mean to catch up (as in overhear); catch with the eye, observe, see; and from that we get to read or peruse something written; and thus to read.
ēligō
Adding the preposition ex (ē in front of consonants), adds variants of ‘from’ as in ‘out of’ to the meaning, thus ēligō means to pick out, thus choose, elect, select, and can be used for e.g. ‘to be chosen by God’, thus ‘saved’.
dēligō
Adding the preposition dē, adds variants of ‘from’ or ‘off’ to the meaning. Thus we get choose out, select, gather or pick off fruits, and a notion of distance, giving choose out and send, and rarely take away.
sēligō
Wiktionary’s entry on sē lists it as a prefix, presumably taken from de Vaan, but I cannot check this entry to confirm this. The entry lists apart-. aside-, away-; and privately without, lacking, wanting, and -less. Gaffiot & Lewis and Short simply lists this as accusative and ablative of suī, which expresses -self as in himself, herself.
The meaning of this word thus becomes ‘to separate by culling out’, thus ‘select’, which admittedly is harder to get from the definition of sē listed in the older dictionaries.
sortior
The verb comes from sors, which means ‘lot’, ‘chance’, ‘share’, ‘destiny’, originally from Proto-Indo-European *sers meaning ‘bind’. Thus we get meanings such as to cast, fix or assign by lots; and thus allot; and from Augustus onwards meanings such as share, divide, distribute, choose, select, obtain or receive.
dēsignō or dissignō
This verb is made from the preposition dē and the verb signō, which means to mark, sign, stamp. Thus we get to mark or trace out, describe, designate or define; to point out, mark or denote by speech; contrive, devise or perpetrate; and further to dispose, regulate, arrange, appoint, ordain, nominate, elect, choose.
How to select your verb
The first option, optō, seems to fit the bill quite well. L&S notes that ‘to wish, wish for, desire’ is ‘the predominant signification of the word’. Without knowing your background, it still seems to suit quite well given what we do know: Vītam optō means not only ‘I choose life’, but also ‘I desire and wish for life’. I would say that is a quite positive message to tell both one self and the world.
As I understand legō, it doesn’t seem to be the best option; it’s primary sense is connected to variants of plucking or gathering, hence the meaning to read (gather words from a page). The derived verbs, however, could possibly be worthwhile considering.
The first one, ēligō, could work, if you would like to express the notion of picking from some options; I would think it possible to use this (but would definitely need some input from someone more knowledgeable on the following) to express something along the lines of ‘between life and death, I choose life’. It is a strong statement, indeed. In Latin it would be Vītam ēligō.
In my opinion, dēligō would not work in this context; it seems to carry more of a meaning along the lines of ‘from these items I choose this’, quite neutral, and not really carrying something of strength.
I would not choose sēligō either; it appears to be completely mismatched here in its nuance.
Considering sortior, it may perhaps have an element of luck to it. It did gain the meaning to select, to choose in Augustan times, but maybe we are here dealing with a meaning along the lines of ‘I select by chance’. For that reason, I do not think it is suitable. However, if one uses the genitive, it might work:
- In gen., to obtain, receive a thing (mostly in the tempp. perff.; not ante-Aug.): […] Juv. 14, 96: “venerabile ingenium,” […] Pass. part. sortitus […] — Adv.: sortītō , by lot: “sacerdotem sortito capere,” […] — Transf., by fate, by destiny (= sorte, or lege naturae): “tibi sortito id obtigit,” […]
In general, it seems to mean choosing something more by chance than by will, and for that reason I assume you will find it unsuitable.
Finally, there is dēsignō or dissignō. This seems to indicate something with ‘order’, ‘putting in order’, similar to English ‘designate’. For that reason, I assume this too will be unsuitable for your purpose.
My suggestions
To me, the two best candidates are optō and ēligō. The first one indicates a desire; as I wrote above, ‘not only “I choose life”, but also “I desire and wish for life”.’ Thus: Vītam optō. The second one indicates having had to select between options, perhaps with a form of detachment to the process – perhaps before being mentally capable of having an attachment to it, but still consciously, rationally choosing it. It would perhaps express something about a previous state, which could serve as a powerful reminder. Thus: Vītam ēligō.
Of course, should you choose to go for the more poetic anima (which could need some explanation when people ask’, you would be in good company with the greatest of poets. Be that you choose that option, I would suggest either Animam optō or Animam ēligō.
Final remarks
I hope that anyone with more knowledge of Latin than me will point out any errors in what I have put forth; I will happily edit what I have written to make this as clear and informed as I possibly can.
Many scholars do not like macrons denoting long vowels, but diacritical marks similar to these were used by the ancients, and in some cases (such as lēgō vs. legō), vowel length is the only difference between the meaning of words. For that reason, I try to always include them. Should you choose to ignore them, I do not think anyone would consider that a mistake. They can of course also be stylised; in ancient times, they were more like long accents at the top right of the letter, an example of which you can see in the below image:

Detail from the altar of Augustus, showing apices over the long vowels: dédicátióne.
Note that in ancient inscriptions, they would not use apices for the letter I; instead they would use what was known as an I longa: a long I. Here is an example from the tombstone for the bones of Agrippina:

Detail from the stone to the bones of Agrippina.
Notice how it says ᴅIᴠI, which in a modern font would be rendered dīvī. Given this, my suggestions, should you desire to render them in a script similar to for example Trajan’s column, it would be something like this:
- Vītam optō: ᴠIᴛᴀᴍ ᴏᴘᴛᴏ́
- Vītam ēligō: ᴠIᴛᴀᴍ ᴇ́ʟɪɢᴏ́
- Animam optō: ᴀɴɪᴍᴀᴍ ᴏᴘᴛᴏ́
- Animam ēligō: ᴀɴɪᴍᴀᴍ ᴇ́ʟɪɢᴏ́
In case the above doesn’t render properly, here is an image:

Demonstration of I longa and apices in a modern font (Alegreya).
In any case, I hope you find help in this, that your tattoo becomes what you want it to be for you, and that I have been helpful. Finally, I have been dabbling with calligraphy for most of my adult life, and have on a previous occasion created a custom rune-inspired font for a tattoo for a friend of mine; if of interest, I could perhaps be of help in drawing up a suggestion based on your wishes; just PM me.
Notes
Where not otherwise noted, the main source is Lewis & Short.