I am buying my first dirtbike, should i get 2 or 4 stroke?

I am 14 and weigh about 140 lbs and i'm 5'6". i am buying my first bike and am wondering if i should get a 2 or 4 stoke. i found a Honda crf100 but i rode a 100 and it was a little boring and would like something faster so i found a Yamaha yz 125. the Honda's a 4 stoke and Yamaha's a 2 stroke. which one should i get and is a 2 or 4 stoke better for a first bike?