Sarah Louise dresses - do they run big or small?

[electra]

I'm looking for a Christening dress for my 2 year old dd. She's only just 2 but if I buy her anything from Gap I always get age 3. In Boden 2-3 is adequate.

True to size in my experience. Dd turned 4yo in May and wore a 4yo Sarah Louise dress in April for ds' christening.

True to size in my experience too.

Dd had an age 4 and an age 6 for general party dresses and wore them at those ages.

Thanks for replies.