Let me say my "story" before I say much else. It all started a few months ago (4?). I was playing a game and I made my name Jas, a male. I've never played with a boy avatar before, so I thought I could try something new. It branched out so much farther than that since then, I love being called he/him and Jasper (Jas is short for Jasper) Whenever my friends on skype call me a girl, I freak out and correct them as soon as I can. They're used to it now, but every once in a while they slip up and it causes my heart to skip a beat. I hate seeing my birth name now. I resent it and I try to avoid using it. I dislike traditional "female" things (dresses, makeup, etc.) unless I'm playing a game. Even then, I don't prefer them. Could I possibly be transgender, or could this just be a phase? (Sorry for the lack of details, if you need more, you may ask.)
You could be, as the two amazing people before me have said, really only time will tell and maybe change it. I've had several coming outs, at first I thought I was lesbian but it didn't seem right. I thought I was just transgender but apparently not. I've come to know now that I'm genderfluid with a leaning more towards masculinity. Like you, I kind of cringe when I'm called she/her or am referred to by my real name..*disgusted face* but I feel good with gender neutral or masculine pronouns. How I feel towards people e.g. romantically/sexually is where I'm transgender. My little boy heart as I call it :3 So, take your time trying to figure it out because things don't always need a name for it. As long as you're comfortable with who you are is what counts.