In the Car

Hello everyone, i really want to have s with my sister but i dont know if she also have this thoughts. We were close and having good times when we are together.

She is 20 and im 24. She asked me if i want to let her drive my car and drive around with her for learning. Because just driving lessons arent enough.
Sooo, does anyone have an Idea what i could do to let things happen?
Oh and she has a Boyfriend, so she is not Single.

Anyone have experience with such a situation? When yes i would like it to knew more.
Thank you all!