Whoever sat in the passenger seat while you learned to drive was brave. Tell them.

Teaching somebody to drive means handing over a situation you can no longer do anything about from the passenger seat. Whoever sat there kept their voice level while you made every beginner mistake, and had to let you make them, because that is the only way anybody learns. Most of their fear went unmentioned on purpose. Calm in that seat is a performance put on for your benefit.

Tell that person you worked this out. Say it directly, and say what it must have been like. They will probably laugh it off, and they will also remember that you noticed.