Perhaps to confuse you even more, gender isn't as simple as binary (being either a girl or a boy), some people identify as variations between the two, as a few examples: some people identify as androgyne (having elements of both male and female), agender (having an identity that is neither male nor female), bigender (switching between male and female) and many others. Some people move between various of these labels and can't pin down their gender, so may identify as "genderfluid".

I also want to say that if you feel like a girl in your own soul and gut, then you are a girl. You don't need to be like other girls. You don't need to be into feminine stuff. If you feel like a girl, you are a girl.