I like girls...should I tell people?

A lot of people uses to ask me if I was a lesbian and I always replied mo because I've never had a crush on a girl and I've had boyfriends and stuff so I always just kind of assumed i was straight because people generally have a "straight until proven gay" attitude, but lately I've been a little confused. I wasn't sure where the line between straight and bi was and I wasn't sure if my physical attraction to girls was typical for a straight girl or not. I had my epiphany when I was reading a glee fanfiction of all things. Blaine and Kurt were walking through a park and cuddling on a bench, just grnerally being cute and in love and i thought it was so adorable and i was like "i wish I could have tha with a guy." bu when I tried to picture it, something felt off. Then I pictured it with a girl instead and it just seemed...right. Perfect. The thing is, I already told people I wasn't gay. I go to catholic school and the only out lesbian here gets so much greof, so much more than the gay males. I don't know her personally, but people gossip about her in class all the time and she's even planning on transferring next year. I'd lose a lot of friends, People would hate me. My parents are Christian so it would tear my family apart. My brothers only eight, how could we explain this to him. I don't want to be ashamed of who I am, I'm not, but I'm not sure of I should come out or keep quiet about it until I've moved out. There are very few out lesbian teenagers in my town so it's not like I'll be having a girlfriend in high school. Im not sure I'm ready for that anyway. What do you think I should do?