How to start out modeling?

I really don't wanna brag, but a few times people have said i should try modeling for surf brands like Roxy and Billabong. I don't have a picture to provide, because this is the internet, and i'm nervous about posting random information up. But, I guess you can say I'm a "true" Roxy, Billabong, Element girl, I surf, wakeboard, snowboard and skateboard on a daily basis and live in Roxy/surf wear, like literally live in it. I have shoulder legenth real blonde hair, hazel eyes and am 5'7 with an athletic shape. Since I was around 13, I have admired the girls who model for them. I'm fifteen. Is this something I should try out? If so, how should i get started??