"I'm 15 I came out to a friend Monday by text while he was on vacation. We've talked 3 times about it since and I can't tell if he's messing with me or if he wants to ask me out (he kept saying he "missed his chance" or if I was still "open"). When I asked what he meant by "open" he said, "Basically, you said you're gay, and I wanted to know if you were available, it was a joke that failed." Now I have absolutely NO idea what he's talking about. He hasn't messaged me back in two days, and I'm freaking out. Is he flirting with me or just making fun of me? I really like him and if I ask him out it could end Really badly."
This sounds like a really confusing situation and there is really no way to know if he is joking, flirting or being mean without asking directly.
He might be uncomfortable that you came out to him and so is trying to cover this up with jokes. This might also just be his style or the way he expresses a sense of humor. It's true he might be making fun of you, but try to figure out if that is the most likely situation before jumping to conclusions. Coming out can be pretty emotional and it's a good idea to try and assess the situation in as level headed a manner as possible.
As another teen suggested, "I think you're overreacting a bit. If he really is joking, it more then likely means he's comfortable with your sexuality, and doesn't mind playing around and discussing it- so if you do end up making a fool of yourself by saying yes, it probably won't be the end of your friendship. My advice is just to wait until he gets back and see if he says anymore on the matter- and hopefully then you'll be able to gauge if he's serious or not. For now, try texting again, but about a different topic, just so you know everything is alright."