Maybe your bisexual. But why even label it. Just ignore what everyone else thinks and act on your own desires. If you're attracted to some girls then fine and if you're attracted to some guys then fine also. There is no hard rule that says you can only love one gender and that you must choose one or the other. Just love who you love. Never let anyone tell you otherwise else you are not being true to yourself. Look on the bright side. It doubles your chances of getting laid. In all seriousness though, you don't need to choose. Just do what feels right. Your attractions may change with time and you may find you lean towards one side and that's fine but you shouldn't try and limit yourself just for the sake of it. Hope this advice helps.
^^agreed. very well put. plus, you're only 13, give yourself some time to mature emotionally. not calling you immature, i'm just saying let you develop into yourself. i'm sure you'll have the answer if you just go with the flow, no matter how long it takes.