Is there such thing as a 'lesbian phase' or can you grow out of it and How long would a phase last?

No there is not a lesbian phase. You either are a lesbian or bisexual or straight. Now it is possible to be confused, sometimes it is possible for people to feel attracted to the same gender even tho they are not homosexual. And it is merely lack of knowledge or experience. Much like someone who has never had strawberry ice cream. So you try it.