The part about the secret makes me think someone threatened him with "Tell us who Superman is or you die" kind of thing.
As far as his age, I'd guess early teens sine he's in high school but hasn't developed invulnerability.
I think, therefore, I get bananas.
When in doubt, think about time travel conundrums. You'll confuse yourself so you can forget what you were in doubt about.
What's the difference between ignorance, apathy, and ambivalence?
I don't know and I don't care one way or the other.
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