You don’t need an AP or IB curriculum to attend an American college. Many international students attended a public high school that followed the foreign national curriculum.
For example, here’s Oregon State’s list of acceptable credentials for freshman admission, by country:
https://admissions.oregonstate.edu/sites/admissions.oregonstate.edu/files/ug_country_requirements_1.pdf
Please don’t write your essays about why you didn’t attend a private high school. Nobody cares. Use the space to highlight your strengths instead.
More importantly, work on your English skills. Good grammar is very important, both for application essays and in your coursework in college.