You are unable to be physically wounded through any means, you can still feel pain.
You are unaffected by disease, and you never get sick.
You are not immortal, but you age exceptionally slow, measured in millennia.
You are not inherently strong, but the strength you gain does not fade.
You are not inherently smart, but the knowledge you gain does not fade.
You are not limited in your personal growth.
(you can become infinitely strong, and infinitely smart, but not without normal effort)
Only you know of your abilities, and are innately aware of them when you reach 21 years of age.
Do you tell anyone?
What do you do with your life?