am i bisexual?

I sometimes find my self looking at men on the internet but out in public i would never look twice at a guy unlike a woman if i was ever given the chance maybe in the future i would try it with a man but i fear it might be too uncomfotable but like i said sometimes i do fantasise about men. I personaly believe bi people would be the better option between the 3 or 4 or whatever i get a bit confuse when people talk about sexualities out side the first 3. But yer i believe the bis are the best form of sexuality because they basically have more options with who they want to be with. What do u think. What exactly am i