Alright, I'm not looking to discuss the show
I was watching the SAO Offline shorts and they had Silica's age shown, she is/was 13 during the first part.

It got me thinking, if we could deep dive into a VR world. Using any avatar.. would there be a legal age required to be having sex?

Theoretically it's all happening in the mind so is there any major issues?

I know games would have to have that stuff programmed in, I assume, so any that did have that ability would get age restricted.
But kids still play GTA so let's pretend they get on it somehow.

If there was age limits and some kid played and roleplayed as an older person and then you got found out how would law decide what to do?