What degree to be a RN (registered nurse)?

I'm a senior in h.s. going to college soon and i'm interested in being a nurse. How many years college does it usually take? Can I be a RN with just an associate's degree or is a bachelor's degree required too? How difficult is it to earn a degree in nursing?

View this post on my blog: http://travelnursesuccess.com/what-degree-to-be-a-rn-registered-nurse