I think we have all thought at one time or another while growing up, watching our parents and how they behave and what they say that and I quote " I will never do what they do, or act like them". I know I did and usually it was when mom was "embarrassing" me by complaining about something, or yelling at me about something I did. I swore to myself I would never act like her, I probably would have said it about both her and my dad but well he died when I was young so he never got to the "oh my god dad you are embarrassing me" years.
Anyways my question to you is when did you first start noticing that you were in fact turning into your parents? Every once in a while I say something but it isn't me saying it, it's my mom. I never catch it before it happens it's always afterwards and I'm going "oh god, I'm my mother!". Every great once in a while I catch a glimpse of her in me as well, I will do something and it would be just like she was doing it.
Even worse, when I was a teenager I don't even remember exactly how old I was prob about 14-15 years old, mom and I were in the car going somewhere and she was trying to open a drink while driving or something and I said "oh just give it here" took it from her and opened it, to which she said that I had just reminded her of grandma with what I said and how I acted. I was mortified at the fact that she had just compared me to my grandmother! But at the same time I thought it was funny that I skipped being her and went straight to grandma.
What's even better is when I am hanging out with mom and she says or does something and does the "Oh god, I'm turning into my mother!".
So my answer to my own question is, I was about 21 when I first started seeing my mom in me.