FYI - The Validating tests in most subjects are given at various times during SWAB summer when the cadets are exhausted. I think math, chemistry and English are mandatory tests that help the staff place the cadets in the appropriate class. Photos of cadets taking the Chemistry validation test several years ago showed about 30% with heads down on their desks trying to get some rest, which depending on your chemistry knowledge, may have been the best use of their time
. The point is, USCGA is set on a 4-year major plan and unlike a regular university, there are no minors to add to a major, so don't feel pressure to skip ahead. Certainly, if you have had the class, especially at the AP level (or college) and done well, take the validation test (if nothing else it is a few hours away from the cadre) then discuss the results with your adviser to make the best choice for you. Even if you successfully validate, you don't have to accelerate, it is a individual choice.
The first semester of any college is challenging. After Swab summer, many will be nursing aches and pains from the physical exertion, combined with the 5 course minimum academic core subject load, swimming/PE class, mandatory sports, mandatory military training, and your new job within your Division/Company, throw in a little homesickness a few room/uniform inspections, and a new roommate not of your choosing and you get the idea.
Even if you had Calc 1 in High School, the academy probably covers it a little different and the last thing you want going into Calc 2 is to have "holes" in your Calc 1 knowledge base. If you are a "high pass" on the test, you are more likely to validate and be successful in the next class, if you are a "low pass" talk it over with your adviser and get their feedback, they see lots of cadets and can provide expert guidance on where you fit in.
All cadets take 1 semester of Physics and 1 semester of Chemistry with a requirement to take one additional semester of either based on their major. Also, I think everyone takes at least Calculus 1.
From experience, recommend admitted students refresh math skills before they attend. Math is needed for both Physics and Chem, as well as math class of course, and seems to be a source of angst for most. USCGA as part of SWAB summer has a math teacher hold several classes for all to prep them for the academic year.
Thanks to trackandfield08 who provided the official guidance above.
Good luck!