Looks cute. As far as "age appropriate" I would say it depends on her interests/likes. Some kids would love it, others would not, claiming they were "too grown up" for something like that. If it falls in line with other apparel and accessory choices she has made in past 6 months I would say go for it. She is hitting a difficult stage... one minute waning treated like a little kid, the next claiming she is too grown up. It is all downhill until she hits about 25 now.
I just saw an ad for a gaming pillow. You put it around your waist, and it helps with your posture. It also gives you a place to rest your arms.
This is what it looks like
This is how it used to be used when not used as a nursing pillow