People's interests change as they grow older. This happens when someone becomes more mature and drops everything that they used to do in childhood. This means that you may feel out of the age bracket or you just want to keep yourself where you are supposed to be.
Because you're too old. Seriously as we age our bodies are constantly changing. Often the lining of the stomach just isn't as strong as it once was, the acid takes its toll over time. Things like ulcers, especially caused by stress also take reduce your ability to stomach things (so to speak) The inner ear & brain control your ability to deal with spatial disorientation. When you spin, get up quickly, shake your head rapidly or go inverted your brain has to decipher what the ear is telling it. when the fluid inside your inner ear moves the hairs inside it, that motion coupled with what you see is interpreted by the brain. Sometimes that ability is reduced, things like meds., illness, damage, disease and a lack of practicing rapid directional changes reduce your ability to keep your cookies down. In the Air Force we sometimes had flight crew members that just couldn't handle the Gs and rapid changes. We actually have programs that these individuals attend that teach those folks how to deal with it. Civilians don't have that readily available & suffer like you--but it can be dealt with