I've never been a teenage girl, so I really have no idea what you are going through. But, I am a dad, and I've been around a while. I kind of know how things go and the level of importance of different things.
Whatever test you think this kid is giving you is of the least amount of importance in the spectrum of all things in your life. Being gay/bi/straight is a nothing thing. Be true to you, stay in school, study, get good grades, further your education, and make a positive impact.
Hm. Well, I think you are taking a risk but you are very young. Not like you are going to marry the guy and he'll leave you when he finally decides that he only wants to be with the same sex.
Being "bi" is much more acceptable now than it was when I was your age. Good thing or bad? I don't know. But all experimenting usually has a profound affect as we look back on the mistakes we've made. Take that for what it is worth. And please don't take this the wrong way, staying up til 2:30 am would have been better spent studying and working on that spelling. If you were my kid----------- I'd want to see a lot more of that than you texting some guy about how he is hot for another guy.
Good luck
P.S.
We are in an age of Aids and STDs - choosing to be with someone who is not making choices, someone who is "doing" or willing to "do" both men and women seems especially careless to me.
My personal opinion:
I would never involve myself with someone who professess to be "bisexual".
Straight OR Gay is okay - but BOTH??!!
To say "I'm Bisexual" strikes me as SO promiscuous.
I'm sincerely curious why would You want a relationship with someone who professes to You that he fantisizes about "this guy"????
If you want to ask him, just ask him. Don't twist yourself into a knot, it is just one event. Good luck, have fun. That's what it is all about.