Is it illegal to play Fortnite under 13?

I'm curious to know, is it actually illegal for someone under the age of 13 to play the popular game Fortnite? I've heard conflicting opinions and would like to get a clear answer. Is there a specific law or regulation that prohibits minors from engaging in this type of activity, or is it more of a matter of parental discretion and game company policies? It would be great if you could shed some light on this topic for me.