Some kids score brilliantly on the first try without studying. BUT you have no idea what kind of background and enrichment those kids had. Were they in excellent school systems? Years of summer math camp? There is no way to tell. Some kids really do improve with study and a second try. I think it depends on the cause of the lower score. If you simply need more familiarity with the test or to brush up on a subject that was lacking your background, you can absolutely raise your score. For example, my daughter got a 26 on the English section of the PreAct. The problem was that our school doesn’t teach grammar and she really didn’t know a lot of the specific, picky rules that were tested.
A bit of study, and yes, some outside help, and she raised her score from 26 to 35 in that section.
It won’t be held against you if you need two tries.