Agree with everyone, highly suggest the lesson. I just went with a friend (first timer) and she went to the lesson. The lesson she took here was all day long.
Another thing is do not pressure her to go into runs that she's not comfortable with. I remember being so stressed out going to the blue runs when my friend insisted i can do it, and saying things like "cmon, look at that little kid, he's bombing down, you can do it too!", that is not a nice thing to say. Even for green runs that are flat, if they are long and the beginner is tired, fell all day, it could take forever to go down that run and traumatize them!