I remember feeling that same way, but to tell you the truth just spark conversation up with him.
I mean I am 19, and now that I look back at all the times I thought " oh It will be weird if I talk to this guy because I like him"i wish I would had just went up to the guy and started talking to him and then gradually asked him out.
Rejection is not that bad, it happens and trust me when you look back at things you will wish that you were a little more bolder, just remeber life is short so why waste your time thinking about the different ways you could had ask him out.