I think it is if your a girl!

It dependshow far the ears are back if they are just slightly so the horse may be listenig to somthing behind them if they are flat back the horse is unhappy or angry

A muzzle

Well I'm 16 to but I'm pretty tall and I weigh about 9.1/4 stone  people say I'm skinny and iv wonderd the same thing lol. My thing is that if you have a flat tummy your not fat! Lol