Abbi
Ski Diva Extraordinaire
Both my 11yo daughter and I wear small adult bike helmets and the S/M works for us. You can see it’s a little big on her face but with the elastic cord it works fine.
My husband is 6’5” and has a massive noggin and the larger size works for him.
The UA mask is out of stock on the UA site. Which saves me from wondering what to use to keep your head warm!