Sizing Runs Very Small

I bought this for my daughter who is a size 2 or 4 in street clothes. I bought a size 4 and she was unable to even get it on. She has been wearing wet suits sine she was 3 years old, so knowledge of how they fit and how to get it on was not the issue. Sizing runs VERY small. We compared it to her old 'youth size 14' wet suit and the youth size 14 was a little bit larger than the women's size 4 of this wet suit. Quality of the wet suit seems to be what we are looking for and I will order a larger size.