But, if this kid did go through puberty at this age, it doesn't matter if he doesn't have the mental maturity to... Well, truly know these things. Maybe she does, and heck, maybe her family is full of people who reach puberty at a young age and are quite intelligent compared to other people at any age. —that ran in my family, both sides... and not to brag, got passed down to me too, but so did quite a few mental disorders—
I'm sorry to say I can't make a clear, justifyable assessment of the situation without actually meeting the kid, going through his history, family history, family line (genetic) history, and interviewing his relatives... But if the case is what I think it is, it's probably too early to label him as transgendered. Probably. But in my experience the youngerones are more... accepting of things than teenagers... maybe going on like this will save him from big mental scarring from the future, like say when he peers have grown up, and perhaps accepted his identity crisis, being educated about it an an early age.