Need help on a really big decision? 10pts for most helpful answer*?

This year, as a freshman, I've been attending a really difficult private high school (400 students) which really helps you prep for college. I can literally only get a 3.0 gpa in regular classes, it's hard. I usually get straight A's in my old school.. have a choice to go to a public school (1200 students) where the classes are simpler and i can work my way up to honor classes with easier assignments. But if i choose to go to public school, they won't prep me much at all for university, but I'll have better grades. Which should i choose? It's really difficult. I feel that i have more scholastic potential at public school, but it will have a lot more social for me. I really don't know what to do at this point. My full potential is not shown at the private school, it might be better for me at a more simple public schooling. HELP! * thank you very much!