While I'm not dating now, in my late 30s through 40s, most of the women I dated were significantly younger than I was -- biggest spread being 23 years (she was 22, I was 45.) It wasn't that I was chasing younger women, it was just they were simply far easier/more open to dating (something I never expected that surprised me when I got older) than women near my age.
In my 30s I'd probably have been comfortable with someone who was 19, but in my 40s the maturity gap was pretty severe with the 22yo. I also dated a 25 and a 26 yo in my mid 40s and we were much more able to carry on a relationship outside of the bedroom.
Honestly, your chances of getting with an older guy are basically 100%. Getting guys isn't hard, getting/maintaining relationships is hard.
To be taken seriously, you're going to have to control tendencies to get too dramatic. The older guys are, the less drama they tolerate, and they're also much less susceptible to being manipulated with sex (though you can definitely entice them to date you with that!) Older guys will love that you're young and hot and cute -- you don't have to dress in a mature way 24/7 to date them -- but to be taken seriously you'll also need to control yourself more than a typical 19yo, and will have to be able to behave more maturely on occasion.
Depending on how much older he is and his social circle, you might have a relationship that is only known between yourselves. It can get pretty awkward when a significantly older guy (mid 40s) brings someone that young to a dinner party or what have you. If the guy were in his early 30s, it probably won't be nearly so big of a deal.
The bigger the age gap, the more both parties end up having to do the dating/interest dance and be obvious about it. A classier, normal older guy isn't going to hit on you if you just flirt with him -- we're used to the flirting game and younger women being "cute," and we'd never put them on the spot by crossing the line -- so you're going to have to drop some very heavy hints or just get downright blunt about getting together. The 22yo I dated in my 40s said things like "boys my age are just boys, I like older men, and besides girls mature faster" and a few other old-guy pick up lines that worked well.
In short, you can't be very passive. This might be a hard thing to overcome as it is for most women just interested in guys their own age.
The other reality is most wide age-gap relationships tend to be pretty short, and pretty bedroom-focused. There's nothing wrong with that, but if you go into one thinking you're going to land a long-term boyfriend or husband (it does happen, just not often) you're going to be disappointed and/or taken advantage of.