I have bought this suit two years in a row now,we love it. One in late 2014 and one in oct. 2015. My daughter is 12 years old almost 5.7" and 128lb. I got her a size 24 this year and last year. I didn't change the size even though she grew. I see reviews about people getting sizes that are way too big and that will defeat the purpose of a racing suit. This suit, out of the box will look like it should fit a toddler. That is normal. Even with the right sizing it will feel like you can't get it past your thighs, even worse, hard to get past your bum. This too is normal. Take your time to get it on. It will be even harder to get it on after warmup when skin is damp. Give yourself extra time so you don't stress out. I also have an 11 year old swimmer but she isn't mature enough yet to deal with the work involved to get a suit like this on. This suit may need the help of an adult to get on for the first couple of times and this is normal for most tech suits. I don't advise sizing up if you also fall into the next size category unless you are well into the next size. Make sure you rinse the suit well and hang to dry. If you leave it in your swim bag too long it will start to wear out fast. Great suit, love the fit if you are smaller chested. My daughter just swam a 29.32 for 50meter free, 2:20.93 for 200 meter free 1:04.25 for 100 meter free and 4:56.00 for a 400 meter free. We swim meters in Canada, not yards. Best times for her and got her AAA times. We will buy this suit again…