GoOutdoors is a great place to check out kit, especially expensive kit like tents. Gives an idea of what you need to look for even if you don't buy from there.Go to GoOutdoors and have a wonder round with her and find out what size of tent she wants.
If you going to do some car camping a tent you can stand up in, a porch and no sewn in groundsheet are really useful points.
I'd go for a large bivvy bag for shared body heat