Nancy, I think it is wonderful that you want to "pay it forward" or back, if you prefer. And I would recommend that you pick the place that intimidates you the most. If you spend any time at all with the residents in a nursing home, you will definitely reap much, much more than you sew. Most decent nursing homes have an activities coordinator. Why not contact one of them and offer to start a quilting class, or bee, or some other kind of quilting or sewing project that can be tailored to the residents? You might find that the ladies (and maybe even gentlemen) would love to do something like sew or knit or crochet blankies, caps, or lovies for preemies and babies in the local charity or county hospital or low-income daycare. The possibilities are endless.
If you are at all musical, you might consider having a "sing-along" session featuring the songs of the thirties and forties. I'll bet you everyone knows all the words to "Daisy" "Surrey with the fringe on top", "I'll be seeing you", "bicycle built for two" and many more!
Good luck and God bless.