Hi, my daughter is only seven and a half, but is 4 foot 5. She also needs jeans to be generous around the bottum and thighs, poor little thing takes after me. 
The monsoon bootlegs used to be a good fit, but they don't seem to be making them any more. I don't like skinny jeans on her, I much prefere comfortable bootlegs or streight. She is narrower around the waist, sso adusters