S.K.
K.,
I think there are many advantages of working as an RN, I have been one for 8 years and have enjoyed it. I didn't have children when I got my undergrad nursing degree, but I was raising one and had my second while I was in grad school. Many schools offer some of their classes online, which I think makes it easier for moms and other busy men and women to fit school into their lives. There will always be a need for nurses, and there is such a variety of jobs available in the field I think everyone can find the right fit for their lives. Of course it can be hard work, some jobs being more physically exhausting than others. As a single mother I imagine you will be working full time for the pay and benefits, but if your situation changes at all the flexibility in schedules that nursing can provide is another nice benefit. I would recommend that when you interview for jobs later, ask for an opportunity to chat with a few of the nurses currently working that job. It can really help you get a better idea of what the work environment is really like, for example how supportive bosses are of family needs/situations, the physical demands of the job, the intradepartmental/intraoffice interactions, etc.
I don't think you can ever be "to old" to further your career/education. My mother was an OR tech for most of her life, then she decided to go back to school and became and RN at the age of 55. Three years later, she couldn't be happier with her decision. I wish you the best.
~S.