Your accomplishments, including the Silver medal in the Medicine Olympiad, put you in the category of qualified applicants to Stanford and Ivy League schools. But as others have said, there are many qualified applicants, and only a small fraction of them will be admitted. Your admission chances are certainly higher at say Cornell than Stanford, but every Ivy League college remains a reach.
You can certainly apply to these reach schools, but be sure to have a good set of match and safety schools.