Hiya, I'm currently in my second year of a masters in social work so I can let you know something about my experiences.
First of all, ring the unis you're interested in and they will tell you what kind of experience they are looking for. I know there are people on my course with an unrelated degree but with work/voluntary/personal experience of social issues, so the experiences you have may count for something, depending on the uni.
At my uni (and probably others) there is an emphasis on understanding not only the role, but also social work values and ethics.
You don't have to memorise these as you can demonstrate them without even knowing of their existence! for example, if you can talk about how you helped your nana to maintain her dignity in her final years, then you have demonstrated one element of the values. If you've ever advocated on your nana's behalf, e.g. with a doc, that would demonstrate another.
On the practical side, it is HARD!! I have two DCs, 3 and 5 and Iots of family support, but I'm knackered all the time. If I had to work as well (as others on my course do, even with children) I'm not sure if I would still be doing it. On the masters you have to do two 100 days (6months ish) work placements, which can be up to an hour and a half travelling time from home! I'm lucky that they were able to find me one nearer than that, but you end up working and commuting all day, come home, kids to bed, then hit the books til you drop.
I can't begin to think about how hard it would be with a baby/young toddler, when you might not get any sleep as well.
But, saying that, I'm soft and I know many women are much more hardcore than me and just get on with it - only you know that about yourself!
On the positive side IT'S ACE and I love it! I would sit in lectures grinning 
There's always the option of applying for 2012 then deferring a year too.
Good luck and PM me if you need owt else! 