tell me your experiences of being with a girl for the first time

After my last relationship with a male I have started wanting to be with a girl sexually, I don't have any desires to be in a relationship with a girl; only a boy but whenever I picture myself in a sexual situation it's always with a girl and never a boy? I've never been with a girl before and it's almost like I want to try or something. Making me feel weird not knowing what sexuality I am