Early submission will demonstrate a serious interest in the program and reflect your good planning skills. Applying early may also increase your likelihood of receiving scholarship money. While these strategies do not guarantee success, you will have more time to recover and plan if your request for scholarship funds is rejected. Problems may arise during your application process, such as transcripts or recommendations not arriving as expected. By submitting your application early, you are allowing time to address those issues and not miss deadlines.
Most business schools accept applicants from a wide range of undergraduate backgrounds.
Keep in mind that curricular prerequisites at most schools are a condition of enrollment, but not admission. In other words, you could be offered admission conditional upon completing certain courses prior to the first term. Take steps to complete prerequisite coursework early in the admissions process and before your planned enrollment date. If your quantitative skills are weak, take courses in calculus or other quantitative topics to strengthen your skills and improve your application. You know best what your weaknesses are.