I don't like online dating anymore, but back when I was 19 years old, I had the idea to set my age preferences on Tinder to 30+ only (while displaying my own age as 19). Had a hunch there were older woman out there that had a thing for young, innocent college guys, and that there would be less competition.
Well, I was right. Quickly matched with a woman probably in her early thirties that was very direct and DTF. Big, fake tits and a really nice body too. You can read more about it here if curious:
https://www.skilledseducer.com/threads/lr-i-meet-my-match-almost-full-on-threeway.14989/
You'll probably get a larger dating pool if you set your age to 25, but you'll have a LOT of competition. It may be better to put your age as 28 or even higher, and then set your preferences to strictly college age, and see if you can find any girls doing what I did. Lot of college chicks with a kink for older guys - I once had the misfortune of going up against a freaking 40 year old with a sportcar and his act together when trying to get with one of the RAs in my freshman dorm.