You'll take a college entrance. If they deem you failed, you'll go into remedial classes that serve no credit. You must pass them. Math is what's holding me back currently but I'm going to try again. I've been out of school for over 20 yrs so I am practicing math like crazy until it becomes 2nd nature to me. Then you do your Pre-Reqs and we starting from scratch, may have more to do than just Bio, A&P etc. those will depend on the school and your goal needs to be As & Bs to give you a better chance to be accepted into a Nursing program. Pre Reqs can take anywhere from 2-3yrs and that's before you've even gotten to Nursing school. I've done a lot of research. I'm 38 & well, although I wish I was younger as long as you're breathing it's never to late to follow your dreams.