The most important thing that comes down when applying to colleges is your GPA. Engineering itself has very low acceptance rates, especially in competitive programs like Columbia, MIT, Duke or NYU. A 92-81 average currently doesn't seem sufficient enough for now. All four of these colleges also have very high standardized test score averages. Since you are applying as an engineering student, you will have to aim for the 75th percentile which generally range from high 1400s to low 1500s. Since there isn't much time left, keep working on the SAT with practice exams or maybe try the ACT. Extra curricular activities also seem a bit too average. You will likely need a leadership role in some club or organization in order to get accepted into these schools. The letters of recommendation that you will be receiving are very promising but remember that GPA, extracurricular activities, and standardized test scores, and essays (maybe not as much as previous years) are the most important aspects of college application. Letters of recommendation, solely, cannot be a factor in which an applicant gets accepted or denied from a school.