If you can't see yourself with girls in sexual or romantic contexts, while you can with boys, then you are straight! Being bisexual requires romantic/sexual attraction, if you only feel that for men you are straight, even though you appreciate women's beauty and personality and you may enjoy sharing contact, but not in a sexual way.
Most likely. However just wanting to kiss a girl and not have a relationship doesn't mean you are necessarily wholely attracted to girls. Sexuality takes a long time to explore and sometimes we pressure ourselves too much to find the answer when we don't need to. Do whatever feels Natural and right to you and gradually you may work out how you feel.