Anakin appeared to approve of Harry's suggestion of an age line, and Harry was grateful for that. Even though the child's age was different in this universe than it was in the universe the child came from, that didn't appear to pose much of a problem. Harry merely needed to make the age restriction a few years older than the child's age. That he could do.
"I could make the age line, and then apply some protective spells as well, so no one could view the bike if they are outside of the age line. I could even attempt a few spells that would make it impossible for the bike to be removed from the age line unless it is physically moved."
He moved around the bike, studying it for a moment. "And if you want verification that the age line is in tact, I can make the age restriction higher than my age, so I can show you how it works?"