Age required to trade in iPhones?

I'm 17 years old and I want to trade in my iPhone 6 into Gamestop for some credit towards a PS4. So what age do you have to be in order to do this? I have a state ID (learner's permit) to show them my age. Please don't tell me to sell it on Amazon, Ebay, or Gazelle.

I'm 16 and i have traded stuff in with gamestop so i don't know where you got this notion for an age limit but i'm pretty sure it does not exist sir.

Prob any age with a guardian or parent