My 2¢
Go slow but often.
20 years ago I could hardly walk or hold a knife and fork due to Rheumatoid Arthritis (40 years old)
Meds got things under control, but working out, starting out holding cans of beans, religiously, got me back to being functional - bought weights once I got stronger. Slow process, but if you push too hard you'll hurt yourself and end up going backwards.
Discretion is the better part of valour.
luckily, I've been in remission and med-free for 4 years now. Still do the exercises and I hike and bike a lot.