This is one of the first things I made for the American Girl Doll. It fits her just fine. If you would like the pattern it is Simplicity 5733.
The pattern was very easy to follow. The one thing you should not neglect to do is it is turn up the hem on the sleeve before you sew the sleeve closed. Lesson learned.
I used a pair of jeans that no longer fit my daughter I thought they would be perfect for a jean jacket and skirt. The skirt is not in the pattern - that was my creation. I used the actual hem of the jeans for the bottom of the skirt.