My first impression of Alice was around 37yo.
There is always a margin of error of 2 years either way so anywhere from 35 to 39 is plausible.
Anyway it doesn't really matter - she is the manager/owner/mamasan - she is not one of the girls.
Alice is friendly, efficient, honest, and IMO sexy but not super hot - and that's what you want from a mamasan.
I really like the way she gives you an honest summary of the girls available and never tries to force a girl onto you, and gives you the option of waiting for a top girl to be available or seeing another girl who is available now - she's a very ethical mamasan and that's quite rare in this industry.