It's okay for them to ask... I probably wouldn't do it in a first session.
It's very important to know what you're doing. Obviously get consent (duh), but start slow. Maintain eye-contact and closely watch what's going on; how she responds. Start with gentle pressure, and ensure your grip is in the right place, and only gradually increase.
If there's every any question, or doubt, STOP!
If she asks you to stop, STOP! If you have little or no experience or you're nervous, don't do it, or, save it for a time when you can maybe double up with another provider who does have experience, where they may already have a trust relationship with each other.
My 2¢