Yes, on the Navy side, both the NROTC program as well as BDCP will help you pay for college. If I recall correctly, BDCP will only do the last 2 years of your school, but it is a good deal, and they pay you as an active duty enlisted servicemember on top of tuition while you are finishing up school....the catch is that you need to attend OCS following graduation to actually get your commission. A nice thing about this program is that you can get a pilot guarantee prior to attending OCS.
I did NROTC and actually started the program when I was about your age, following a couple years in a part 141 flight school. Did 4.5 years in the program, and they covered all but the first year of it (in terms of tuition, fees, book stipend, and a monthly paycheck that varies from about $250-400 between your freshman and senior years). It was a good program, and gives you a good deal of military training while still allowing you to enjoy the college experience at the same time. You do summer training "cruises", which are normally 3-4 weeks and you can end up just about anywhere around the world. I did one cruise on the USS Kitty Hawk in 2005 from Sydney to Guam, and in '06 I did about 4 weeks @ NAS Lemoore riding in the back seat of Super Hornets. While I have friends that did OCS and BDCP, I think the NROTC program is a little bit more well rounded, and personally I would not want to have done USNA or OCS so it worked out nicely for me.
As for the prior experience thing, to echo what rp said, it just doesn't mean a whole lot. I never mentioned it to anyone unless they asked (which at times they will be able to tell for sure). Your instrument experience will be helpful in primary, and just generally having some "air sense" will be a big payoff, but in terms of stick and rudder skills and the various steps throughout the training syllabus, you will be back to square one in a lot of ways. I feel like I had a decent advantage in primary over some of my friends who didn't have several hundred hours of civilian flying to fall back on, but we totally evened out by the time we got to advanced jets. It's just a whole different ballgame, and the areas of emphasis are completely different than those of your civilian experience. That said, with the right attitude, your experience will help you do well and get what you want. Just know there are a lot of other hard working guys out there with no prior time that are just as competitive, and will at times do better than you in some areas of flying for whatever reason.
Overall, if you have an interest in serving, and in military aviation, I say absolutely go for it. There is nothing like this anywhere else in the flying world and if you have the opportunity to do it while you are still young, I see no reason not to.
