Guys my age don’t seem interested in me while older guys do, why?

I’m about to turn 21 and the last boyfriend I had was in high school, for a while I enjoyed being single and had no interest in dating but now I’d like to entertain the idea of potentially having a boyfriend again and getting into a more serious relationship. Ideally I’m looking for someone in my age range (21-25), but any guy who has expressed interest in me is typically not in that age range (usually 27+). While I’m not against dating older men (as I have been with older men) I do feel like there will be an obvious difference in interests and wants, and I do want a more serious relationship (not just sleeping with each other). I do look a little bit older than I am (people typically assume I’m around 23), but I don’t see why that would be a turn off for someone who’s 21-25. I’m 5’6, 125 lbs, somewhere between strawberry blonde/red head (turn off?), blue eyes, fair (turn off?), some freckles on my nose/cheeks/shoulders but not that many, with curves but leaning more towards a slim build. Could it be that my age range just doesn’t find my looks conventionally attractive? I tend to be a little more shy in certain social settings but are definitely social when I’m out at bars/clubs/parties (which is where most of these guys are), but it still seems like they aren’t interested. In the least conceited way possible I know I’m not ugly or unattractive, it just seems like I miss the mark for guys closer to my age. Is this just a string of bad luck or should I shift my ideal age range to older as it seems like there is more interest there anyways?
Guys my age don’t seem interested in me while older guys do, why?
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