When did you let your kids start gaming?

Genuinely curious about the range here. My 7yo is asking for Fortnite because all his friends play it. I haven't let him yet - I've read the stuff about the rating and some of the toxic chat behavior. But I also don't want him to be the weird kid at school who can't play with anyone. Is there an age where it just becomes unrealistic to hold the line? What did you do?