Is it possible to start out at, let’s say, 20 years and be sharp as a knife. Never forgetting things, never dropping things, always have an answer ready and can do multiple things at once. And then around 30 you suddenly drop stuff you have in your hands, you forget if you locked the door, your contactlenses have gone missing from the storagecontainer, people need to stop talking while you drive?
I don’t think such a significant difference should happen from 20 to 30. You probably have an issue of some kind. It may be something simple as insufficient vitamin intake or such, but I’d suggest looking at your lifestyle and giving it a thought.
People often joke about how the body at 30 is already half-way to a zombie but it really shouldn’t be that bad. Source: I am 40.