Parva mihi domus est sed ianua aperta;
'My house is small but the door is open.' (lit. doors)
This is the first line of Mus ariddle found in Symphosii Scholastici Ænigmata given in full on Gianni A. Sarcone's site
For 1st person, mihi est, and 2nd person, tibi est, this is by far the commonest way to say "my" "your," for possession (but not invariably ownership).
In Philip Baldi & Andrea Nuti p314 (Constituent Syntax: Quantification, Numerals, Possession, Anaphora (sadly, £90; but tasteable)) four forms are discussed, which I have oversimplified here:
Genitive Marci est domus (limited to 3rd person)
Adjective meus (tuus/ eius) implies possession and ownership and physical presence.
Dative mihi est, tibi est (but not 3rd person) more widely used than meus,
Habeo habeo is most widely used of all because it includes non-possessive (Ihave a cold); immaterial (I have a bad feeling about this); momentary ( Let us have lunch).