I too did things backwards, having children first, then I went to nursing school. I waited until my children were in school full time before I started. I started out slow doing summer classes at the local community college to build a good GPA before I applied to nursing school. Some advice I would give you is: take all the sciences prior to going to nursing school, save things like sociolgy and psych to take with nursing, if you decide to have children first, make sure your husband is like mine and is willing to run the houselhold or at least do the majority of running the house (nursing school is all encompassing), and make sure you and your husband have a strong marriage because this will test it, and try to have a good support network around you (friends and family).
Nursing is a wonderful profession, but it is very physically and mentally draining. Make sure this is something you truly feel a calling for because it is not a job that I would recommend soley for the money, or flexability.
Often the job is not as flexible as you would like, and if you decide to work in a hospital such as I do, you will work many holidays, and many times not what you place as your preference, as well as working weekends.
Good luck with whatever you decide.