Hi,
Good for you for going back to school and finishing your degree. I've known a few graduate students who were older (sometimes by a good bit) than the traditional age bracket and a few who were raising children as they pursued their degree. I never understood how they did it. It's tough enough even when you're in your early-mid twenties, single, and childless.
My degree is in biological psychology, a.k.a. behavioral neuroscience. In other words, I work with rats all day and do lots of behavioral testing, drug testing, and surgical manipulations. I'm just beginning a post-doc in which I'll learn how to apply molecular techniques to the same sorts of problems.
Good luck! I hope you enjoy the new techniques!