Hello there,
Having strong grades in math and science subjects, which are relevant to mechanical engineering, is a good start.
Though remember that while grades are important, determination, passion, and a strong work ethic can also play a significant role in your success as a mechanical engineering student. It may take some extra effort, but with perseverance, you can achieve your goal of becoming a mechanical engineer.
Also you can apply to multiple universities to increase your chances of acceptance, including a mix of competitive and less competitive institutions.