I agree with Eden. I am small and I am not growing taller at age 54; it's increasingly difficult for me to buy anything. I can wear x-small jerseys that have no elastic. I hate elastic! I weigh 106 lbs and the jerseys still ride up on me. So, I mostly have Terry jerseys and a couple of Voler club cuts for women because they seem to be the only ones that make extra smalls with no elastic. I like some of the Shebeest jerseys, but some are actually too big on me in extra small. I was able to shrink one by washing it in hot water a few times.
I think that whoever makes jerseys needs to pay attention to people at the outer edge of the size spectrum; half the time when I go to order stuff from Athleta (regular athletic clothes, not cycling things) the petite x smalls are sold out because there is such a run on them.