Where is the best place in San Francisco for two young females to live?

Me and a friend are planning on moving out there after graduating high school. We want to live somewhere relatively safe but fun for young people. We'd like to find an affordable 2 bedroom townhouse/apartment/condo to rent, but we don't know where to start looking! (We're from the east coast) She's a lesbian so she wants to live in a gay-friendly area. I'm a beach lover, easy going type of personality. So we want to live somewhere that fits our personalities.