Two types of girls look for older men, Those who have daddy-issues, and gold diggers...
(edited to add/qualify, that's for girls looking for guys 10+ years older.. most young girls do liek younger guys, but usually in a subtler range, 1-5 years, just maturity and successfullness that many guys in their late teens/early 20's don't have right away...)
now, in the age range you're looking at, where they're well-into adulthood, that changes quite a bit, and is not as valid, but you have to have somethign they want that makes them want a guy who's 10 years older. Good job/ money/ lifestyle? Highly educated? Travel a lot? Lots of adventure and youthfullness in your life? sports/ working out/ going out, still enjoying life/ learning/ adventure?
To be blunt a lot of women are looking at you as a 50 y/o man, and if you want late-30 y/o's you should be in that condition/ competition group. Match.com if you're looking for longterm relationships, but that is BASICALLY an interview, and women can screen hundreds a day so yours has to be the best profile, layout, most exciting, most intriguing, etc. One of these PUA Gurus has a 'pimping your profile' rundown .. I think maybe christian?.. I dunno, I know Bill Preston knows though, maybe some of the other mods?
my assessment of the situation (completely amature) given my limited knowledge of the situation is that you might have better luck with women in this age group meeting in person in situations you can impress them with your youthfullness, either at the gym, or beach or sports leagues, or anywhere you can really shine at things you're good at.
hope that was more help than hurt
gl