At what age did you become an expert?

I remember growing up it was about the time I became 13ish I became an “expert”. I knew it all and my mother could tell me nothing. I had all the answers. Because I was an expert and did not listen to her I lost two bikes, one of which I slaved all summer long for working. I believe at some point all young people want to flex their muscle or stretch their wings and most show it by avoiding their parents as if their parents were dog doo doo, or bucking heads with every small thing their parents come up with; after all they are experts. What age did your “expert” gene kick in and what did it cost you either in material things, relationship, family ties, etc?