As you begin your search for possible colleges, it's good to do a broad search online to gather information. A quick search for "public health undergraduate programs" for instance will produce a myriad of results. But with all the information that comes back, it's sometimes hard to know which is the most reliable and you can easily get overwhelmed from the sheer magnitude of information that can be found on the world wide web.
Start by looking at resources that you recognize, such as Peterson's or US News and World Reports. If it's in a specific field, search to see if there is an overarching entity that accredits the program; for example, the Council for Education on Public Health (CEPH) for the study of public health. In addition to the information that can be found on ceph.org, an overview of public health programs can be found at https://www.bestcolleges.com/features/public-health-degree-programs/. These resources can help inform about the different types of programs as well as the names of the universities that offer them.
From the vast array of programs, you can then begin to narrow down your choices based on the type of university you want to attend as well as location: public, private; large, small; etc. You may also want to consider which programs feed into specific schools of medicine or other graduate programs, as I see that you may be interested in becoming a doctor.
Whatever you do, try to approach it slowly - trying not to get overwhelmed by all the possibilities. Consider your priorities within your pursuit of higher education, and take it slow and steady. The more time that you spend with it, the more likely you'll be able to find the right program for you.
Best of luck to you!