Welcome to the site! I’ve found it to be a great resource in locating trails around the Atlanta area. I am around the same age as you (I’m 44) and have just gotten back into mountain biking after a several-year layoff. I ride Blankets and Olde Rope Mill. I also try to hit Clinton Nature Preserve 1 x week, and the closest trail to me is Yellow River in Stone Mountain, which is not very challenging but a good workout nonetheless. If you ever want to hook up for a ride, let me know.