Just a quick thing for those of you who are parents... you will be fine!
I have no kids, I'm not married etc and I am a 35 year old woman. And as weird as it sounds, this actually caused problems for me. Unfortunately at my uni almost all the mature students were parents and they grouped together, understandably, to compare their methods of handling the life/uni balance and to talk about their common ground - children.
Because i didn't have the same 'life experiences' as them I wasn't included, I will admit that the comments of 'it's ok for you, you have no commitments' were hurtful, and assumptions were made about me due to my assumed lack of commitments. I think I just had the bad luck of meeting people who were a little judgemental, I'm sure others aren't all like this.
I actually ended up becoming friends with the younger students, and not all of them (especially after 1st year) want to go out and get wasted every night, so chilled out nights in the pub, gigs and coffee/lunches and evening meals still occurred and I mixed with a variety of people.
If you are a mature student with children you will find dozens of similar students, if you don't have kids you will still fit in!