In a world that is constantly changing there is no one subject or set of subjects that will serve you for the foreseeable future let alone for the rest of your life. The most important skill to acquire now is learning how to learn.
Wrinkles should merely indicate where smiles have been.
Anyone who stops learning is old whether at twenty or eighty. Anyone who...
Age is an issue of mind over matter. If you don't mind it doesn't matter.