Converse size

[beardedladydragon]

I am buying my daughter some converse. She is a 2.5 with very narrow feet (E width). Should I get a 2 or a 3 which then goes up to adult sizes? Thanks

[PNGirl]

I'm a 6 and once bought a 5.5 which crippled me if that helps? It was the length that did it, rather than width.