I've had this conversation with my non-binary child. They point out that if you don't know, you should say they/them, and when identified, absolutely use the identified pronouns.

Your kid is wise!

...she is very strongly female and as such would be offended by any pronouns other than she/her.

The prevalence of people who are, as you so well put it, are very strongly female, and who are also really big on presenting as femme/feminine/etc., is a BIG reason I ultimately worked out that I am in fact genderqueer--- I have absolutely no desire to present as femme/feminine/etc. and I don't want to take their presentation away from them (or even give the appearance of doing so) but I don't want it imposed on me either.