As Re-invent youself over & over said, find something you love and go for it, nobody cares about your times except for you.
Here's some advice:
Don't be "that guy" at the office who looks like Shamu in a tie who always insists that he ran 14:25 in college 10 years ago, but is now such a pathetic pile of blubber, whose only refuge is to say "I coulda been a contenda" ... that's great and all, but nobody cares.
I always loved to run, HS, college, and post college - I was good in HS, middle of the road in college, won a few heats, was always on the traveling team, got a letter every year. I kept running after college mainly because I ran on my own even before I ran on my own even before I ran on a team in HS.
For me, running is a bit like art, there are some people who are very good at painting but don't necessarily like it, then there are those who may not necessarily be very good at painting, but they MUST paint - it is simply something inside of them that must get out.