Trade in PS5 Slim for PRO

I would like to trade in my digital Slim PS5 into GameStop and pay the difference in cash for a pro. However, my son who is five is starting to really get in a gaming and I would like for him to have his own. It isn’t a necessity, but do you think I should make the decision now and only have the PRO or maybe wait and have a pro of my own and a ps5 for him?