Personally, there's a specific range when I'm looking for a partner. There's no range when I'm just DTF. I've seen a young man with an old ass lady (wrinkles and all) making out. Do I have a personal opinion about it, sure I do. Will I go towards the two couples enjoying each other's embrace? Who the fuck am I telling them what they can or cannot do? Same concept when someone tells me, she's too young or she's to old. I respond right back, saying, "So?" 99.9 percent of the time they don't say shit after that; I say, "Do you think I give a fuck what you think?" for those 0.01% that feels like they have some sort of impact in my personal life.
My question to you is: How do you feel about him and how does he feel about you, emotionally?
If the whole age is such a deal breaker for you, then don't pursue? If not, who gives a shit how others would feel about it. Seriously. If this really is part of your criteria/preference when you're looking for a potential partner, then set yourself a range limit... who knows someday you'll find someone that doesn't even fall in that range, but you'll make an exception... lol
If this is just for sex, then go for it! Who gives a fuck about age when you just need to be stimulated down under.
For me, personally yes because my last two girlfriends were 6 and 8 years younger than me. I felt they were mature so that's why I felt it was ok. But because of their lack of dating experience, when problems arose in their life, they'd prefer to run away from it. Or in our relationship, just change subjects instead of dealing with it. But also when I'd talk about music or pop culture from my generation, sometimes they'd be like "what's/who's that?" And I'd be like cleantechnica.com/files/2015/07/happy-sad.gif
I don't necessarily think that is too much of a age difference. It is cutting it close those. Continue to hang out with him and see how things progress, don't rush things. I suggest at least waiting until you turn 21.
A lot of relationships that I have seen break up when the somewhat younger individual becomes 21 and can go out an drink for some reason.