1st Position Flex Lace Up Pyramid Toe Jazz Shoe - All Questions

This is our first time buying jazz shoes for our daughter's Stagecoach classes. Our daughter is a UK size 1 but almost is a size UK 2. But your website seem to say getting a size 1.5 bigger than your child's usual size. Is that normal? I wanted your advice as we have never done this before. We appreciate your advice and look forward to your prompt reply. Many thanks.