This dress is designed for an 18” doll. I have no personal experience with the American Girl dolls, but I am pretty sure this dress would fit one. I knit it out of Regia Flusi. It took one skein. It was great yarn to use and the color is so much fun. I think any doll would be proud to wear it to any summer picnic to which they were invited.
I knit it on US 2 needles; I think I would use US 3 needles next time because I am a very tight knitter. The pattern is very quick and easy. I did the sleeve holes slightly differently because I did one in the round and the other flat so I had to change the pattern so they would match (the pattern was unclear about how to do them and I prefer to knit in the round when I can).
This pattern is out of Sock Yarn One Skein Wonders. I love all the One Skein books and this one has a ton of great patterns in it. There is a large list of ones I plan to do when I get time.