Having started TKD a couple of years ago and being in my late 30's I know what you mean. I want to relate an incident that happened a little while ago at our school...
We had been practicing back kicks for about 15 minutes and the instructor stopped us. He made us get up in front of everyone else and perform two back kicks (one with each leg). He then judged if they were good enough or not and told us so. After my first kick he told me to make it higher so I redid the kick and barely made the height requirement. That was my left leg which is much more flexible than my right leg due to an old rugby injury. I knew I could never make the height with my right leg so when I kicked I unloaded everything I had on the bag. I know I hit it at a point lower than he wanted but I managed to kick the bag over. It went straight over too, it didn't pause in the middle waiting for the water to catch up and tip it, it just slammed into the ground. I got a round of applause from the people who were watching the class. The instructor said it was a good kick. Nobody else that night managed to come close to kicking the bag over.
What does that incident show? It shows that a lower but more powerful kick can be just as effective as a high kick. It shows that a good kick does not have to be a high kick and that you can still impress people with some show of power.
You are at a transition point, you have been there for a while but you have only just noticed. You are transitioning from speed and agility to power. No more showing off by jumping and spinning, instead you can show off by breaking equipment. They still will not let me to flying side kicks due to structural damage from the last time I did it
Let the younger crowd jump and spin, that is what they can do best. Your best is changing, use it to your advantage.