Falling apart?

Ever feel like your body is falling apart? This can happen at any age but when you're over 50 it really hits home. I've been training for a half marathon later this month and have had a sore knee for over a week. I don't think I'll make the race. I was running it to raise money and awareness for the Blue Planet Run Foundation so it will be a big deal if I can't make it. I really shouldn't complain. My body has allowed me to do many things including dance and run 20 marathons. Is it telling me it's time to rest? No, I hope not, because my mind hasn't caught up with that idea yet. I am grateful for all the things I have done and look forward to the things I will do in the future.