The boy in my other classes

So there is this guy that's in some of my classes at (high) school, and he's kind of been eyeballing me and staring at me in class quite a bit these past few weeks. I know him and he knows me but we're not really "friends"; we've only spoken a couple of times. Recently (though this might sound stupid and irrelevant, it's a big deal to me) he followed me on Instagram, which he apparently doesn't do to many other people, so it's kind of unusual. I really have feelings for him and I think he's really cute, not to mention he's a real romantic according to one of his past girlfriends (he's bisexual and yes he's had relationships with guys before). Should I try to make an effort to get to know him better and try for something more than just a friendship or should I just leave it where it is? Because according to his exes and his close friends, he wouldn't be doing all the things he doing if he wasn't interested, but I honestly don't know.