Running was a staple in my life for several years. Injuries, laziness, job layoffs, etc., happened, and it became an "explanation" for not running. My last competitive season was 25 years ago.
Yes, there were some attempts to return, but none as successful as this past year. The hardest part was to forget what I did do, and work on what I'm able to do now. In previous return attempts, my mind was remembering what I did a long time ago, and I was burning out trying to keep at that.
Start out with a distance and pace a lot less than what you think you can do, and just relax. Build from there. Years ago, my main workout was 8 miles at 7 minutes pace. Last year, I started out with 500m at 8:00-8:15 pace, and built up to 5k.
Why not 8 miles?
Simple: I'm older, my responsibilities are a lot different now than they were years ago, and time is a very valuable resource that I must plan for. I consider myself blessed if I have 45 minutes to change, stretch, walk, run, shower.
Will I run a low 16 for 5k and mid-33 for 10k again? I don't know. I'm 56, not 31. But, PR-ing in this new age group will be something worth trying.
Good luck to you.