Dress for Signorina Quattro's birthday next month:
It's vintage simplicity 6990, in the 1970s seersucker bought at the vintage fair last month. It has an 8.25cm hem, so it can be let down as she shoots up.
Edited to add:
I made a reversible pursible for her too! I made it a little bigger than half size, for cuteness! It's reversible, but I used the same fabric for both sides: