I think 12-year-old me would be happy with current-me. After all, I'm still essentially everything I strove to be when I was 12 in terms of fandom, only more mature and at a saner level. In terms of personality I haven't changed all that much; I'm still very much my own person, only without the pre-teen angst and the level head of an adult. I think the only thing 12-year-old-me would find disappointing is that I'm not as outgoing as I used to be, but present-me is very happy with the level of reservation I have now. So overall, I think 12-year-old me would be happy. And I would tell her that yes, you were right, my mother was wrong, you would be keeping that pokedex for years to come.