I don't think it's ever to late to get involved in the community to the degree that you're able to. It may not be the success you pictured but there is worth in contributing to anything.

Try not to think of it as making up for what was lost because you'll put expectations on yourself that may paralyze you and prevent you from trying something new. I have pretty terrible anxiety but have learned to just do it, anyway. Therapy groups/out patient programs/volunteer things are usually a good place to start socializing. Baby steps!