That is a great time for your first 5K!
My first one was about 14 years ago at the age of 43. I had quit smoking the day before, I was not overweight. I walked with my wife and kids, I think my time was over an hour
....it was in a town I spent 3 years as a kid....took a detour to show them the school I went to 1/2 through the race
however....I have continued to do them...probably 75 or so PLUS our very own 5K's with our dogs.....
I did get into the high 20's but that was a while ago...now we walk them for fun....
KEEP GOING!!!