if you change your major while in college, will you still be able to graduate on time?

It depends which major you changed from and to. How far along were you in the first major? Do the two majors have similar pre-reqs? A lot of people change their majors and are still able to graduate on time. If you have extra coursework that won't fit before you were expected to graduate, you could try taking summer or Christmas courses in order to still be able to graduate on time.

Generally, yes. The first two years of college are focused on core classes that everyone needs to take. Your specialized courses begin in your third year. Changing majors within the first two years should still allow you to finish within 4 years. I changed majors in my second year and was able to finish on time. It's important that you work with your college counselor to map out the courses you need to take to finish on time. You can take summer classes to catch up if you fall behind on your plan.