being shy means you are gay now?

Yesterday my brother asked me if I'm gay (actually I am but still in the closet) because my cousin(who is lesbian) asked him this cause I'm shy, don't speak too much and don't go out often. I mean being shy means you're gay? She's just dumb(what I think she is for this and others reason) or it's just her "gaydar"? I'm not ready to come out.