Some help with a story, please!?

Weell...i wud say i know nothing about horses but you know you could write a story about a girl from the countryside who wants to become a great horse rider someday maybe? Or how about a horse who suddenly finds itself in human form and size? And about the non horsey thingum...how bout writing about a boy who has big dreams blah blah...but is an orphan and stuff? And a girl who becomes prego in high school and has to raise up her kid and stuff...not a bad idea..