You will find the link to the team store on the swimtopia site. 
Competition swimsuits are all sized the same across brands. I have never noticed a difference. Most girls who wear sizes 8-14 (even 16) will be in a suit sized 30 or 32. 
Boys sized 10-16 will also likely wear a 30 or 32. This is based on the sizes that my kids have worn for the past 5 years. 

I was made aware that the sizing tool was giving out funky sizing. So, I wanted to make sure to make this announcement. If your old suit fits great. Order the same size. If it is too small, order one size bigger.