Teenage girls always want to know whether that guy they saw glancing over is interested in them or just stretching their neck. It's an important question because if a glance means that a guy is flirting with you, then you need to react to this attention differently. Maybe he is not interested, or maybe he's just too shy to make a bold move like walking over to you and asking you out. But how do you know? You can find out more by checking out the how to tell if a boy likes you guide.
The first thing you need to know to find out whether the boy in question is actually flirting or not, is what kind of a glance it was. Was it a quick glance? Did he do it multiple times? Does he do it to other girls too? If he seems to only look over at you and not in other directions and he seems to do it often then this might be his way of showing interest. So how do you know if this is his way of flirting? You could try doing the same thing to him! Something weird happens when you immitate someone else's behavior, they tend to think of you as being more similar to themselves and they then form a stronger bond with you. So if you want to see if he likes you and if he is trying to flirt with you, you might try glancing over at him too. Remember not to make it a long brooding stare, you just want to let him know that you know he is looking at you.
If he immediately stops glancing over at you, then you should stop too. It either means that he realized he was checking you out and it scares him to think that you know that. Or that maybe he wasn't interested in the flirst place and he just got a bit weirded out by seeing you glancing over at him too. Just relax, if this guy is not flirting with you there is nothing to worry about. It doesn't mean that he doesn't think you're pretty or cool, it just means that he is not interested in you at the moment. There will be more guys glancing in your direction soon enough, so take it easy and get back to paying attention in class.