Well I'm 26 and I don't have a car, house or job! I'm in the same position as most uni students, I'm just a bit older and have experienced some different things.
I think it is quite common for girls to prefer older men especially if they are a bit more mature themselves. Once you get a bit more older and self assured you stop playing games. I see my younger male friends acting oddly around girls they like, eg they will become moody and get into arguments with them as a way of getting attention from them, or send them mixed signals to keep them keen etc etc. I don't think you get this crap from older males they know how to be straight to the point.
My last ex was 18 and I was 25 at the time, and I'm sure the age was part of her attraction to me. She had newly arrived at university in a strange city and was unsure of herself and probably felt some security in going out with me rather than a 19-20 year old second year, because I knew what I was doing and wasn't there to mess her around. It also looked impressive to her friends who all had their 6 form boyfriends from back home, that she had "pulled" a guy 7 years her senior.
However from the older guys perspective it can be difficult sometimes. I realised after a while that, nice enough girl that she was, we didn't have that much in common because there was such a gap in life experience. I felt like I was looking after her more than me being able to get a lot out of the relationship.
Ultimately I think the attraction to an older guy comes from female desire for security, some older men already have tangible evidence of being able to be a provider (if they are in a secure job), but apart from that there's a level of emotional stability that older guys can provide better than younger headcases.