From my experience teen boys are a whole lot more immature than teen girls.
From my experience from what I have seen in the first world countries or the West. They are both immature beside immigrants from the third world states but I'll say the difference in my opinion.
Teenage girls - Attention seekers especially when posting ridiculous status or photos on Facebook on other social sites when no one cares, edit their pictures using photoshop/instagram all the time, doesn't dress the way girls used to wear, addicted to techs, obsessed with famous teenagers. For example, when Justin Beiber came to Australia, in my city and performed; all teenage girls shed tears, pushed each other to reach the front and they even pushed the guards and went thru. This shock the whole Australia...oh god how embarrasing.
Teenage boys - They are doing everything what the teenage singers are doing like Beiber, One Direction etc, dressing this so called word "swag", buying thick glasses, tight jeans, using instagram/photoshop like girls, homo hairstyles(mostly indie haircut), hip hop and everything.
I'm referring to them who lives in the West, not third world countries. So, pretty much the new generation of teenage or youth 'music' style and 'social sites' or the internet destroyed them.
They would probably commit suicide if electromagnetic pulse(EMP) hit their state.