If your school’s not helpful in giving guidance, think about where girls like you, with your goals, have gone the past few years. Start networking. The flavor of some sems change from year to year.
Now I assume you’re looking for E”Y, so I’ll get some chu”l options out of the way. They are very worthwhile if you’re thinking chu”l too: Detroit, Manchester, the “other” Gateshead sem, Montreal. I don’t know about NY options like the new one in Far Rockaway under Mrs. Feiner and other.
Off the top of my head, here are some Israeli sems: Chcohmas Lev, Peninim, Shoshanim, the half year sems (wonderful people affiliated with the sems, from the ads, probably more hashkafa oriented and concentrated)
BTW, if your grades are consistent (I mean you don’t roller coast but do the best you can on a regular basis) and you’re good and sincere, you should be able to find a sem. Hope you find good advice, advisors, etc.