@CameronBameron 2,265 answers, 8,645 votes
If your school uses Naviance, then log into it and make a college list and see how students from your school performed in the past 5 to 6 years based on their GPAs and test scores. And if your school doesn't use Naviance, then I would set up a meeting with your HS counselors and ask them to share with you their opinion of what matriculation criteria were present in the past for students from your school to get admitted to the kinds of schools you are applying to.
There is absolutely no magical cutoff for GPA. Each high school calculates it differently. I went to Deerfield Academy where a 93% average is considered high honors due to grade compaction. So 90% of the graduating class has less than 93% and about 10% have between a 93-95%. But there are plenty of DA students who get into Ivy or Elite colleges with 90-92% GPAs. But if you compare that to Harvard-Westlake in CA, then 67% of the graduating class has a 92.5% GPA or higher. So with rampant grade inflation, it appears that everyone from HW is a genius when this is far from the truth.
The real answer lies in the acceptance rates/matriculation rates for high schools. Deerfield has a 30% average Ivy acceptance rate and a 22% matriculation rate. This means 30% of DA seniors who apply to Ivies get in and 22% enroll. At Harvard-Westlake, it's like 24%/17%. So this informs you that regardless of what your GPA is, all college admissions offices use GPA in the context of the course rigor and grading system of the HS to determine who gets in and who doesn't. Another thing to point out is that there is more likely a higher density of legacy and recruited athletes and fac brats and rich donor kids at East Coast boarding schools compared to California.
Good luck.