Boy, that is one beautiful bag/wallet!! If you like charms, go for it! Don't ever let age stop you! I personally think this bag is gorgeous on its own!
I'm 38, and I always put a charm on my coach bags. It's one of my favorite things coach offers. Usually only one and I prefer the brass ones (the coach heart, bleecker charm, etc) but I also have fun with my owl, flower, koi fish and skeleton. Go for it!