I occasionally miss a scheduled day due to my kids activities so I just go to my next workout the next day. I assume that back-to-back days are not adviseable to do in order to play catch-up, especially for a 45 yo.Is this true?

If you are doing a total body routine, such as a 3 day per week program, it is probably best that you don't go back to back days as you mentioned.
Generally, it is a good idea to allow a muscle group at least 48 hours to recover following a training session, so if you are doing a total body routine, you would not lift back to back days. Besides, as long as you are consistent over a long period of time, missing a workout now and then is not going to ruin your progress!