I want to be a model?

i am so passionate about modeling its something i would like to do during my teens.skin shade im a black girl,im fourteen.loads of people at school say im am pretty.my brother says i should do modeling.i really wan to send an Application to elite modeling agency because they are scouting for girls.what do modeling agencies look for by the way.i have big eyes,normal shaped to pouty lips,skinny body but don't have cheekbones i think i still have baby fat help please what agencies in london are looking for someone like me .