I definitely think most girls in our society are allowed more freedom of expression, but sometimes that is constrained by religion. I myself grew up in a secular family and with very little pressure to conform, although of course there were pressures, mostly from my mother. I always disliked female things from a very early age, and always identified with the men in my life. I can't remember a time that I did not; I just naturally looked up to my father, my uncles. I did try to act normal for a period of my life, probably from age 6-10, but it was with much struggle. I don't remember much, if any, happiness during that time of my life. It was when I was most anxious.
After that time, when I became a happier person in some ways, I started to present differently. More masculine, yes, but for the most part just trying to conceal my changing body. I was very overtly uncomfortable and awkward. Puberty obviously worsened that exponentially. While there were a few setbacks, I mostly began to present more masculinely as time went on. Along with that, I was developing a male alias online and identifying with male characters in literature-- finding my footing, you could say. When I was 13, I pretty much viewed myself as a male, but often struggled with my mother's attempt to make me assimilate. She was merely confused and trying to help, I see in hindsight, but I often felt under attack. At 16, I was going through an identity crisis and couldn't continue school.
I'm 18 and I started T exactly one month ago. I wish I'd done it even earlier, because already I have sacrificed a lot for it. My education is still incomplete; I am still uncomfortable with the idea of continuing it because of my increasing paranoia and discomfort with people.
Yes, it does seem there is an upsurge in young FTMs and I believe that may be caused by the greater acceptance of masculine women. I was tolerated, in a sense... I certainly wasn't bullied because I scared the crap out of some kids. I was tolerated as a freak, and in a sense, I think being so nonconformist helped rather than hindered me in this respect... The focus was not on my gender or sexuality, but instead on how eccentric I was on the whole. Wearing male clothes was pretty much an afterthought if I wore a cape as well...
On the other hand, it may come down to an individual's sensitivity. It has been shown that individuals in identical environments will grow differently based in part in genetic makeup and individuality... I believe myself to be a little too sensitive. I naturally have a very hard time conforming and coping. I would be a goner without transition.