The therapist undoubtedly mentions the restrooms to all of zir potential clients, just in case it's relevant to them. Zir job is to help people become comfortable with themselves, and there are those who feel most comfortable with gender-neutral restrooms. (I've been in quite a few professional offices where there's just one restroom, which is like a home "half bathroom" that only accommodates one person at a time, so gender isn't even an issue. But I'm a completely cis, if fairly butch, female, and I wouldn't mind using a gender-neutral restroom if that's what there was.)
The therapist will probably ask you what pronouns you prefer, which will give you a perfect opportunity to ask zir which ones she prefers. You don't need to explain unless zie asks, and/or if you feel you need to.
no subject
The therapist will probably ask you what pronouns you prefer, which will give you a perfect opportunity to ask zir which ones she prefers. You don't need to explain unless zie asks, and/or if you feel you need to.