Say so on the phone. A decent instructor will start in a quiet car park, talk through the cockpit drill, and not throw you at a ring road. You can ask for a female instructor, shorter lessons, or a parent to sit in on lesson one.
Caffeine, no breakfast, and a bad night’s sleep all make clutch control worse. Treat lesson days a little like test days: water, food, and a buffer so you are not sprinting from work.