How long will it take me to be a RN?

im a senior in high school so im starting to look at my career opportunities. im thinking about working on a bsn pre-licensure path at csu stanislaus. i was wondering, if i were to take this path, when would i actually be able to obtain a career in nursing, like by what age? would i have to get my masters degree? ive read that this path takes four years, but does that include your first year in college, or do these four years begin after your first two years at college? i am sooo confused, please help!