I like a younger guy?

Long story short, I like a guy who is about seventeen years old. Only issue is, I'm twenty in a couple months. It's legal and all, 16 being the age of consent in England, but I feel iffish about it.

We used to like each other about two years ago but didn't really admit it openly. After getting back in contact with him lately I've been struggling with the feelings that returned alongside him, and I don't know what to do. I think he knows about it now and flirts with me openly.

I know it shouldn't really matter, provided it's normal enough - he's extremely mature, intelligent, taller and is even going to uni at the same time as I am next year - and I look a lot younger for my age (people assume I'm 15 the majority of the time), so it wouldn't look out of place publicly.

So, what are your thoughts? I just feel guilty about the whole thing and I don't know what to do with myself.