Need Leopard Gecko Help on feeding

Hi - I've had my leopard gecko for over 16 years and have had no problems. He's always been active and healthy. However, for the past few weeks, I've noticed that he is struggling to eat. We've been feeding him superworms forever without any problems until recently, and now he struggles to eat them. He shows interest, tries to catch them, but has a hard time hanging onto them and eating. He has to make several attempts to get it then the worm just falls out of his mouth.

We thought the worms are getting too big - and with his age, thought he would do better with something smaller, so we just tried with mealworms and the same thing - it's as if he can't grasp the worms. He does eventually eats them. But I'm worried that he will not be able to eat enough.

By the way, his tail is still quite fat - as fat as his neck and he looks great. Just concerned about his change in eating behavior.

Is this something to do with his age? I thought may be he is just getting old. But if it's something else and there is something I can do so that he continues to eat well, I would appreciate any tips and suggestions you can give me.

Thank you!