Wedding outfit for a tall and thin 12 year old

[Crwban]

DD is 5'4 and extremely thin for her age (think 20" waist). She is very narrow all over. Getting clothes for her is a bit of a task. She's too tall for children's wear and definitely too narrow for older children's wear, never mind adult clothes. We have a family wedding coming up and she'd love to feel special and dressed up. Everything I see doesn't suit her or looks too short on her long limbs. Help! Do any of you have any suggestions please!

Should have added that she's really pale, freckly and has amazingly orange hair. Not all colours suit her.

Try Ted Baker children's wear. Their dresses suited my very thin long limbed DS at 12. Age appropriate too.

Silk shift dress type thing?

Seconding ted baker, they also go down to size 0 (4 in uk sizes?) in their adults section, so that might do?

My niece has a similar frame to this at 9 years old. We brought her a debenhams Bridesmaids dress in a size 6 and paid to have it altered x

My daughter wears a size 4 from ASOS. There aren't many retailers who sell in a size 4 but you will get the length you need.

Fab! Thanks everyone. Off to have a look.

Actually I just looked again at ASOS. They have a petit range which goes down to UK size 2.