1) It is not too late!
If you are really worried about being the only older student in your subject, then why not contact the place of study that you are considering. You can ask them for the average amount of mature students taking your chosen course each year. They will be more than happy to help you and knowing that you are not the only older student should help to put your mind at rest.
2) If you want it bad enough, you can overcome almost anything!
3) Take advantage of any free workshops on offer to help you brush up on your study skills.
4) Try and get involved within the university community
5) Book recommendation!