I am just a random somebody around your age in previously mediocre but now significantly improved shape since starting kickboxing. One of the most important things I learned is that all that most age related “injuries” and “soreness” etc is counterintuitively almost always caused by _lack_ of exercise rather than being too active. In fact it’s probably impossible to be so active as to outweigh the benefits you’d get, it’s basically entirely a positive feedback loop once you get started. (Note I am not talking about people who have suffered serious physical trauma and need to recover, that is something else entirely—-just more like an average couch potato).