There's such a gulf of experience between those who have children and those who don't...I regularly volunteer with elementary-age students and am always surprised at what they know, even though I faintly remembering being "smart" back then.
I just didn't think 3-year-olds would understand or even be introduced to possessive pronouns...I can't even conceive the linguistic path it takes from saying the first word and other nouns to understanding possession and "me"...Although I guess "mine" is pretty easy for them to figure out as a way to get things :)
When my brother showed photos to his young son, he'd say "...and that's me" when pointing to himself in the photo, so my nephew assumed that was his name. ("Me, Me, what's for dinner, Me?") He now understands pronouns, but seems to have also kept "Me" as his dad's name.
People don't realize that little kids talk, all the time, and especially to anyone who spends every day with them, it's clear when they are developing new concepts in their mind - they go through a cycle of linguistic scientific experimentation, testing the waters, so to speak, on their newfound grammatical mechanics or vocabulary.
I just didn't think 3-year-olds would understand or even be introduced to possessive pronouns...I can't even conceive the linguistic path it takes from saying the first word and other nouns to understanding possession and "me"...Although I guess "mine" is pretty easy for them to figure out as a way to get things :)