My daughter is ALSO a senior in high school. She'd originally planned a 2-year RN (so she could work for decent wages while she completed the RN-to-BSN) but then decided to go for the 4-year-degree. She's considering joining the Reserves or one of the armed forces to help pay for school.
A two-year degree is great because you can be done in 2 years if you work hard, 3 years if you are working while going to school (you can get your "extras" out of the way before you actually start the nursing program). Community colleges are often less expensive than universities and you may have the option of living at home in that case (which will also save you some $$$).
A 2-year degree is INTENSE. Plan not to have much of a life for those two years if you go that route.
A 4-year degree is great because your opportunities are a little wider as soon as you get out of school. You've also had MORE time to get used to medical terminology
and the whole college experience (I know that the 18-year-olds in my nursing class had a tougher time because they hadn't had the life experiences of the "mature women" -- didn't want to say "older"!...then again, the students just out of high school tended to have MUCH more time to study and more energy. What can I say, there's always a trade-off).
If you LIKE going to school and can afford it, a BSN is probably the most bang for your buck. If you need to work right away, a 2-year program gets you out and earning...and you'll only be 20 or so...you can spend another few years working while you finish up a 4-year.
On the other hand, if you don't like school and you're not a good student, the 2-year program is your better bet (and then you can take years and years to finish the 4-year...one course at a time). Some of the courses you will take at University are designed to widen your experience as a human and won't necessarily be valuable to you as a nurse...then again, you never know. It's the disciplines least connected with our own that sometimes give us the best and most creative solutions to problems (for an example, see some of the nursing research done with music in nursing homes).
Keep in mind that either way, you're a nurse. A 2-year degree doesn't mean you can't get a 4-year later.
You won't get rich as a nurse, but you won't starve either.