Crushing, what to to ??

So I like this boy but the problem is I am shy and awkward but not like super super shy or super awkward but anyway he is in .and one of my classes and I don't know how to go about getting him to know I like him , we have causally conversation sometimes about the subject we are in and little other stuff and I would be more open and flirty with him but there is too many people in that class for me to comfortably talk to him and also I feel like I'm kinda not good enough for him because I'm kinda chubby and he is really cute , I know I am a pretty girl though but also I know if he is interested in me that won't matter for real and just to put are ages out there I am 16 and he is 17