Sounds like your DD is just about exactly the same size and age as mine! We have a medium that fits beautifully (I think we're on the 3rd tightest snaps for waist and thighs, but might be 2nd on the thighs, can't remember
). I haven't measured it but the rise seems higher than what I saw quoted on Jabula's site, it's plenty high enough at any rate! I do have a large on the way but am a little worried it'll drown her, I don't really like nappies having to be on the tightest snaps all around