Hi there! I'm in the nearly the same situation as you, except that I'm married and have an almost 3 year daughter, finishing up a degree and working full-time. The best advice I can give with regards to managing it all is to learn to be VERY efficient with your time.
Know your time-suckers and try to eliminate them from your daily schedule. For example, for me, I tend to be very tidy, but I've had to learn to only do laundry on weekends (saving class readings for trips to the laundromat), and, in general, give up on trying to keep things perfectly neat around the house. Or, I have to limit my time checking email outside of work to no more than 15 minutes otherwise I will get distracted and jump right in instead of writing a paper or responding to a class discussion.
Be able to find and use small blocks of time whenever you can -- you will need all your spare time to fit in your school work. But, be sure to schedule SOME time to yourself, because you will need it!! Time management is a MUST and the sooner you can master that, the easier your life as a student and employee will be. For some free resources, just do a Google search for "time management tips" -- we'll be posting some articles on time management soon, too.
Also, before you officially enroll anywhere, consider test driving a free online course to get an idea of what it will be like ... don't wait until the last minute to get acquainted with the virtual classroom -- it will be different everywhere, but you can start to get a feel for it.
By the way, I think you're in a good spot to start your schooling now, without a spouse or children to worry about ... you sound very motivated and looking into strategies for success early on is a good sign that you have what it takes to be a great student ... good luck!!
P.S. Also check out our "Guide to Online Education" for a great primer on online education -- http://www.elearners.com/guide/ -- especially the How-To's section ... http://www.elearners.com/guide/online-education-how-to-guides.asp