I think it has to do with stress vs. recovery. Not age, directly.
Consider a lifelong runner. If they run 3 miles every day, can generally they run every day without a problem? Yes. But if they have only run twice in the past year, can they run 3 miles every day? No. It's not enough time for tissues to adapt, and all the other physical adaptations to occur for the body to handle running 3 miles a day. It will take some time to build up to 3 miles in even a single run, and when they get there it may take a day or two to recover from it. But when they do, it will serve as a training stimulus, and they will improve their body's ability to run.
Slow increases. Measured doses of stress, followed by adequate recovery (rest, sleep, nutrition). That's how you transform a body's ability.
It is the same with S&S. Each training session is your measured dose of stress. It is a moderate daily load; "if you don't have heavy days, you don't need light days" and rest days. It's possible to do it every day, if your dose of stress is just right, and you are recovering from it, therefore adapting to a higher level of ability.
Basically if you are progressing, you are fine. Don't worry about your age.
If you're not progressing, and you feel like the sessions are hard, and you feel better after a day off, then perhaps you are pushing too hard in each training session, or your recovery is not good enough to do it daily (due to age, life stress, hormones, or some other factor). Either back off the intensity just a bit (if you want to train every day), or back off the frequency to 3-4x/week.