Yes it’d definitely distinguish you, especially if you’re applying to a top university/LAC (or a university where foreign language fluency is important, such as Middlebury or Macalester, or expected, such as HYP). This would be most important if you plan to apply for Humanities/Social Sciences.
It’d be better if you took the AP Spanish exam this year, unless you intend on taking AP Spanish as a class senior year.
If you are Hispanic and spanish is your second language, what good is AP spanish? If you are bi-lingual already in Spanish, just put bi-lingual on the application or trilingual if you are able to with the Italian. Take a different AP class. The trilingual is most important.
Just because one is a heritage speaker of Spanish (or Chinese, Korean, etc.) does not mean that one is able to read and/or write in the target language.
^This, ten times. Heritage speaker does not mean native speaker, and while being heritage/native helps for the SAT Subject, the higher level required for AP means the person has high fluency in all linguistic skills (reading, writing, speaking, listening) used in a culturally-appropriate context.