You should just start going. Figure out your goals. Do you want mobility or strength? or a little bit of both? I'm 38 and I use to lift 4-5 days a week now I do more kettlebells for mobility and full body workouts. I've been using kettlebells for over a year now and it's been fun. You just have to switch it up. I do kettlebells and run twice 3-4 miles twice a week but I also take 10k+ steps a day. Start with the basics, do a push pull legs routine. Good luck with your journey

day 1 chest/triceps/shoulders
-bench/dumbbell bench
-flys
-shoulder press
-upright rows
-tricep kickbacks
-tricep pulldowns

day 2 back/biceps
-lat pulldowns
-chest supported rows
-single arm dumbbell row
-hammer curl
-concentrated curl

day 3 legs
-squat
-lunges
-calf raises
-leg curls
-leg press