You need to take a set of courses and be in the top 10-20% for each of them. So you won’t be a biology major and you’ll have to do better than future biology majors in your 2 intro biology classes. You won’t be a chemistry major but you’ll have to do better than future chemistry majors in you 4 chemistry classes. If you’re not among the best in every class, you don’t have a med-school worthy GPA and you have to change focus if you want a health career. Fortunately there are lots of health careers. But you have to be on top of your game every single semester.
The classes you’ll have to take: 2 each of English, Biology, Inorganic chemistry, organic chemistry, physics + 1 each of calculus, statistics/biostatistics, biochemistry, sociology, psychology, a diversity-focused class, and if you can neuroscience and/or knowing a language spoken by immigrants (can be done informally through community education and volunteering at a clinic.)
On top of that you have to choose a major - any major - and be excellent at it. You can pick Philosophy, Music, CS, it doesn’t matter as long as you’re among the best in your chosen field.