I realized that although I’m taking 5 APs next year (my senior year), I will only have 5 APs on my transcript and 4 AP scores submitted. I’m planning to apply to some very competitive universities. Yale, Barnard, and Pepperdine are all on my list. Does this significantly reduce my chances of getting in?
No.
You don’t generally have to report your AP scores until you are admitted and you want them considered for credit.
True, but that doesn’t change the number of AP courses taken/on your transcript, as is OP’s concern.
To be clear, you’ll have taken 10 AP courses total?
I’ve always heard that it’s more about making sure that you are taking the most rigorous curriculum for your school. Will your guidance counselor report this? Often which specific classes you are taking will make a bigger difference than if you took 9, 10, or 11 total AP courses.
Course rigor matters. AP status is just one piece of this.
For a lot of the privates, they ask for a grade report around early November. So they’ll have a sense of how you are doing in the course at that point. The in-school GPA is more important than the external 4 or 5 anyway for the purpose of admissions, unless you are coming from a school that is considered not rigorous, and you need that external validation.