Krypton, it was the planet you were from. Your parents sent you down to Earth before its totoal destruction. You were (age) years old.

After a bunch of space traveling, you crashed into the middle of a giant field on Earth! You roamed around for a bit, not noticing the sort of...hysteria or destruction your arrival created. So you roamed around in the aftermath and came across a truck that was flipped over. You saw a man in there. So you used your strength to help him out. Soon after, he was now carrying you, and covered your naked body in his jacket

Jonathan : "You're not from here now are ya?....definitely not from Kansas"

He saw the spacecraft you came. It was confusing, but it confirmed a lot. And he wasn't even mad about his truck being flipped over. You sorts saved his lifem

Jonathan : "oh I can't keep you kid...I can't..."