I want to be older!and I am just 10!?

I am 10 and my absolutely biggest wish is to go to middle school but I am still in 4 grade.And I am not mature ok I started developing at 9 and boobs are developing and all that stuff but sometimes I act like a little 7 year old...and I just wanna be like my 14 year old brother he is aloud to do everything!He says that in middle school there's a lot of work,but they can use cellphones and they are aloud to swear.And I am jealous and no one else of my friends has this problem is it even normal in my age?I feel like if I just wanted to be like anyone else! I just want to be 14 and I have been working on not annoying older teens.I am fine with being a tween but being a teen must be better!And anytime i have a crush the 10 year old childish boys will scare away they are so stupid even though 3 of them are my friends:Doh god and my mom says I have already hit puberty and my feelings are already and the world uh....god!Please help me!