help with snuggy hood sizing

[gonebananas]

I need to get my 2 year old filly a snuggy hood head for her sweet itch but i'm sure what size to get her. she got a free fly mask with her derby house rug which is XS this fits alright but could do with been a little bit smaller.
she's a PBA and is coming up 13.2hh right now, should i get S or S/M
Size Guide
I'm confused

 

[peanut]

If the snuggy hood is too large, the eye holes will be in the wrong place even though the rest might fit.

Personally, I'd go for one on the smaller side, but just make sure you can exchange it if necessary.

 

[gonebananas]

thank you! i shall be sure to make sure of that