I've tried to put these succinctly — and with a certain compassion about the suffering involved in tattooing! — as follows:
Ipsi ago (I act for myself), or pro me solo (for me alone, for no-one but me).
solus eo (I go alone), or non timeo inter homines ire (I do not fear to go among men, sc. through the world, through life).
integra erat ac sola.
ire is a basic verb meaning 'to go' in any sense, which I prefer here to ambulare, which is the verb that actually means 'to walk'. Also, for 'the world' I have used homines, meaning 'men' or 'mankind', whom you presumably regard as the threat, rather than 'the world' itself.
NB — if you are female, you should change both solus and solo in the above to sola.