Ok so since Vassar has an open curriculum with only 3 very flexible requirements… are AP credits even significant? For example would a cognitive science major really need a US history credit? Or is there an importance I’m missing?
I am a parent of a Vassar junior. AP credit is very important in that one requirement to graduation is that one needs 36 credits to graduate. That means that theoretically if you wanted to take 4 classes a semester you would not receive enough credits to graduate. Conversely if you really wanted to graduate a semester early, and save a semester’s tuition, again you would use the AP credit and take five classes a semester. Having those credits in your back pocket can be nothing but good. And there is that one distribution requirement that you need to take at least one math-science and one liberal arts type. Also AP score can be impotent in class placement like skipping calc 1 or Chen 1 or first semester language. Be aware that Vassar only accepts 4 AP classes so if you already have four 5’s AP and there is no placement concerns you are worried about, you may not need to take additional AP test.
PS having those credits in your back pocket could be a life saver if you end up in a couple of circumstances, of course hope you never do, where you have to withdraw from a class or classes late past when you can pick up another one and end up short on credits after four years
I also have a Vassar junior! and she is very happy to have her AP credits- as @robotrainbow says, it takes the pressure off and lets you place out of first level pre-reqs.
CogSci is a great major, but there are some tough courses in it- if you go that route you are likely to have terms when taking 4 classes will be daunting enough.
ps, can we guess you got through ED? if so- congrats! I hope that you are as happy as the Vassar students that I know 
haha yes I was accepted ED, thank you! and thank you for all of these responses