The best way to tell if you are bisexual, or any -sexual for that matter, would be to find someone trustworthy to experiment with and go from there. It doesn't have to involve sex, either. If it feels natural, right, physically pleasing, then it's a good starting point for you to explore your sexuality further and really figure it out. This isn't really a question anyone could answer FOR you, but I'm sure you can find some good tips. Cheers