Bethin is correct. You can become an RN by four routes....Associates Degree (which more than half of us get, and is usually cheaper because they are offered on the community college level), Diploma (which as she said is very uncommon these days), or LPN first, then RN next through and LPN to RN bridge program.
Note that BSN's typically, like most Baccalaureate degrees take 4 years. Associates Degrees require two years of nursing program. Typically pre-reqs take a year, sometimes two if you don't have some very basic high school courses like math, biology, etc. So timewise the ADN might not save you much time.
Also expect there might be long waiting lists. Which is why some people get the LPN first as they might not have to wait so long.
Finally, I'd like to add to what Bethin stated that " BSN is for those who wish to supervise in some capacity in the future, which is true, but the BSN can get you more positions such as in education, research, quality, safety, case management, public health, teaching, etc. There's value in the BSN beyond just being a manager. But ADN to BSN programs are everywhere, even online, and you can do that later. I'm doing it now because unless I retire rich or marry rich I'm going to have to work until I'm 65 and beyond and I'm not sure I can keep up with the physical demands of bedside nursing......however I definately don't want to be a manager, I want to teach. Most places have tuition reimbursement.
Associate Degreed nurses enjoy a wide variety of positions making good money. They take the same NCLEX RN that BSNs do and start out on equal footing, making the same amount of money. The BSN is just an investment int he future - what do you think you want to be 20 years from now in nursing - you really can't answer that right now. You might say "I only want to take care of patients, but like me after 15 years, you might think.......I'm not so sure now". Of course your situation might be different, you might want to retire by then (but you might be broke from sending kids to college. LOL). This is why I advise getting the BSN out of the way. But there are many compelling reasons to get the ADN first which is an option just as equally advisable as the ADN, and in many cases makes the most financial sense. Also, in many parts of the country experience counts more than degree. ADNs get many good jobs in management and elsewhere depending on where you live. In the hospital I work, BSNs are mandatory for most positions beyond the bedside and charge nurse positions.
So a lot of things to think about.