I know how you feel about age, I'm 26 and I'll be starting at Warsash this month on the FnD course. As far as experiance goes, I've done some casual sailing and resoration in my free time over the years but absolutely nothing that could be considered 'industry'. I thought I'd aged out a couple of years back but it was only when I got talking to a couple of people in the industry that I realised I hadn't.
I'd suggest going to an open day and having a look around. At the Warsash open day I got chatting to one the course organisers and it surprised me how they were very open to having mixed age intakes. I had a few age related questions during the interview but honestly, I've never felt like being past that college-graduate age was an issue.
I'm blogging my way through the next few years as I found other peoples blogs to be incredibly helpful so if you'd like a little insight on how the first few months will be as a slightly older graduate, feel free to check it out.