I remember when I was 18 getting back from a three mile run and feeling exhausted. I more or less collapsed on the stairs when I got in the house.
Today, at 45, I enjoyed nearly 13 miles with a good friend and after getting home took my dawg out for a good walk.
I’ve put in a lot of training since I was 18, so being older and heavier isn’t the issue you might expect. I’ve practiced and learned a few things over the years.
What is there that you’d like to be better at?
Put the time and effort in, and you’ll see improvement. You might never win the race, but you’ll feel the benefit and get better.