Is a 3.43 GPA college good enough for Harvard University?

No, a 3.43 GPA is generally not good enough for admission to Harvard University. Harvard is extremely competitive, and successful applicants typically have GPAs significantly higher than that, often above a 4.0 weighted GPA (depending on the grading scale used by their high school). While GPA is just one factor, a significantly higher GPA is almost always expected. Harvard also looks at a wide range of other factors, including standardized test scores (though currently test-optional), extracurricular activities, essays, letters of recommendation, and demonstrated interest.