Generally, the chances for any OOS applicant to UNC-CH are somewhat problematic due to the highly competitive nature of OOS applications there: UNC-CH admits OOS applicants in numbers that are calculated not to exceed 18% of an entering freshman class. See “Undergraduate Admissions” on Page 2, here: http://www.admissions.unc.edu/files/2013/09/Admissions__Policy.pdf. As a further example of the difficulty for OOS students to be admitted to UNC-CH, the entering Class of 2020 had a 15% acceptance rate for OOS applicants: http://admissions.unc.edu/apply/class-profile-2/.
If you look at the UNC-CH Common Data Set, under Part C7 it states that standardized test scores, application essay(s), letter(s) of recommendation, and the rigor of your high school record are “very important” academic factors considered for freshman admission, whereas GPA and class rank are “important” academic factors considered for freshman admission. Extracurricular activities, talent, and character/personal qualities are considered as “very important” non-academic factors.
Further, Part C9 of the Common Data Set for UNC-CH gives the median 50% for both SAT and ACT scores, as well as the percentage of the entering first-year class falling within certain ranges of SAT and ACT scores; Part C11 gives the percentage of entering first-year students falling within a range of unweighted GPA on a 4.0 scale, and Part C12 gives the average high school GPA of first-year applicants.
By way of comparison, our OOS high school usually has 8-10 students who apply, and 1-2 students who are admitted, each year to UNC-CH; and, with the exception of legacy students, our admitted students have composite ACT scores of 33+ and weighted GPAs of 4.4+. These successful applicants also were involved in extracurricular activities that showed commitment over time (no “drive-by” ECs), and demonstrated leadership in the school as well as their ECs. Other kids in our city who I know were admitted to UNC-CH recently also had similar academic statistics and non-academic characteristics; and all of these kids were “unhooked” in admissions parlance (i.e., not a recruited D-1 athlete, or a URM, first-generation college student, etc.).
If you are a URM (“under-represented minority”), recruited D-1 athlete, first-generation college student, or OOS legacy, you may have a slightly easier path. Otherwise, focus on getting high standardized test scores, boost your GPA to the extent you can, and work to have really good ECs, essays, and LORs.
Having stated all of the above, your ACT score is pretty low for most admitted OOS applicants. If you have good essays and letters of recommendation, that will help; or if you are a URM, Carolina legacy, or have some other factor that could work in your favor, that would help also.
I don’t know whether your high school has Naviance or any similar program that gives information about how students at your high school have done in applying to colleges and universities; if so, you might peruse that data. I would also try to meet with a guidance counselor at your school early in the Fall semester to discuss application strategies for UNC-CH; if any former students from your school have been admitted to UNC-CH recently, the guidance counselor may be able to give some insight into how and why such student(s) were successful.
Good luck to you.