John wasn't quite sure why you were so hesitant to join a team.
You were old enough, and perfectly capable, having been taught by himself. Your mind was powerful, and he knew you would make a great asset to a team of powerful young heroes. A part of him also wanted to see the child he'd adopted and raised over the years settle into a pleasant routine - as pleasant as crime fighting may be, but with close friends and accomplices.
"Why are you so reluctant?" John asks softly as he approached you, settling a warm hand on your shoulder. He isn't interested in invading your mind - you could block him out, and he wanted to hear it from you. It was better that way. Although, he'd had an inkling it was because of your origins - the fact that you were a White Martian. Why? He wasn't quite sure.
He tilts his head, his eyes filled with sympathy. "You can tell me anything. I think this would be good for you. What's troubling you?"