My advice is this: Finish your community college, apply for grants and scholarships to go to college in the US, keep in touch with your girlfriend throughout, making visits during every school break, and see where it goes from there. If it's meant to be, it will work out. But personally, I don't think amassing over $100,000 in debt is worth it. Because yes, school in the UK is expensive, and so are the living expenses. Hopefully she is able to understand that limitation.
I'm speaking from a somewhat similar situation-- I met the love of my life at a relatively young age (20) when I was on an exchange in the UK. After 6 months together, I had to return to the US to finish university. We did the long distance thing for 3.5 years, travelling back and forth whenever we had the time off, and money for flights. We've now been together for 7 years. I wouldn't necessarily say it's been easy, but it has made our relationship very strong. I think the main thing is-- I wasn't going to put my life on hold, or force him to give up his in order to be together. That would have caused way too much resentment and/or regret if things didn't work out.
After a few years of long distance, visiting each others countries, and completing your education, perhaps things will have changed and you'll both feel more ready to make the big decision to either get married or move countries. Best of luck.