When his first words are "make it so," you'll know he wasn't too young.
"Live Long and Prosper" works too.
And no, it's not too young. I was born during TOS' first syndicated run after it's NBC cancellation, and my mom used to tell me that she and I would watch it together when I was a baby, and how I would point and laugh whenever I saw Spock onscreen.
Of course, back then, we didn't have anything even approaching the access to the Star Trek toys and other stuff we have now.