My
Middle English mi (originally before words beginning with any consonant except h- ), reduced from min, from Old English mīn (see mine1).
wiktionary
From Middle English mi, my, apocopated form of min, myn, from Old English mīn(“my, mine”), from Proto-West Germanic *mīn, from Proto-Germanic *mīnaz(“my, mine”, pron.) (possessive of *ek(“I”)), from Proto-Indo-European *méynos(“my; mine”).
Cognate with West Frisian myn(“my”), Afrikaans my(“my”), Dutch mijn(“my”), German mein(“my”), Swedish min(“my”). More at me.
An abbreviation of an oath such as my word or my Lord
etymonline
my (pron.)
"belonging to me," c. 1200, mi, reduced form of mine used before words beginning in consonants except h- (my father, but mine enemy), and from 14c. before all nouns. Always used attributively, mine being used for the predicate. As interjection, by 1825, probably a shortened form of my God!
