Can I get implants at 65 after having implants since 16-years old?

Hello!

There is no limit of age when it comes to surgical implants, as long as the area where the implants is needed is in optimal conditions this means that the quality, height and thickness of your bone is good as well as your health in general the study that will help your implantology determine this is a CT scan (tridimensional view) of the area where the implants needs to be placed and even if is not in good conditions make sure you discuss with your dentist about bone grafting.
I hope my answer was helpful.
Regards

You can surely have dental implants!
As you had been wearing dentures for a prolonged duration, there can be some amount of bone loss expected due to being edentulous for years together.
Depending upon the availability of the underlying bone, we can plan to place either 6 or 8 straight dental implants or proceed with advanced dental implant protocols like the All-on-4 technique. In this technique, the teeth set of the entire jaw can be  replaced by placing two straight dental implants along with two slanting implants.

   Please take a CBCT scan to check for the bone ,If you have minimum available bone also ,u shouldn’t be worried because with the new implant techniques like (all on 4 technique) you can have mininum implants placed and achieve desired results With out any bone grafting procedures.
Good luck with your treatment!!