I've got several years on both of you, and while I do frequently feel ancient beyond belief (the combination of rheumatoid arthritis and a much younger girlfriend will do that!), I long ago realised that doing what you want to be doing is vital. We spend most of our waking hours working, use the rest for whatever you have enthusiasm for, regardless of age. I've seen too many people drift out of hobbies and before long they become work/eat/tv/sleep routine people. We have a hobby that is creative, imaginative and metally stimulating. We're the lucky ones.