Hi, Shaina! I totally understand. I'm planning to move over there for similar reasons, and I've done some research on it. I'll share what I've learned so far, since it's hard to find clear answers about this stuff.
I assume that if you're planning on living there for a year, you're probably going to have to work to support yourself while over there? If so, you'll likely need a work permit. You cannot apply for one directly, you must first find a company in the UK which is willing to hire you, and then they must file for the work permit on your behalf. This is no easy task! But it can be done.
There are a few instances in which you could get work over there without a work permit. For example, if you are going to be working in certain industries were there are shortages, like the hotel industry, and you are under 30 (which you are), I think you can get by without one (if I understand the rules correctly). Since you're only 21, I'm guessing that you probably don't qualify for the Highly Skilled Migrant Worker program, which applies to nurses, doctors, teachers, engineers and people with extensive IT experience.
If you were from one of the Commonwealth countries, like Canada, immigration to the UK is a lot easier. Maybe we're still being punished for the Revolutionary War. LOL.
If you're planning on going to a university in the UK, US students can work anywhere in Britain - England, Scotland, Wales and Northern Ireland - for up to six months at any time during the year through the BUNAC program. (Oh, how I wish I could afford to go back and get my master's! Unfortunately, I'm still paying off student loans from my bachelor's degree...)
