I've introduced 4-5 women to shooting. Just guide them with a light touch, and explain the pros & cons of different guns. A range that rents is a big plus to helping her choose. Don't over-rule her unless she picks something unreliable or unreasonable for her.

Then get her formal training with a certified instructor on defensive use of a handgun.

"...the designer of the .270 Ingwe cartridge!..."