Hi, my name is Adam Wolberg, and I'm studying molecular biology. So as soon as you enter BU , even before if you're undeclared, you will have an academic advisor. You and your advisor can start working as soon as the first day. All you have to do is just email them. Sometimes they'll even reach out to you as early as the first week of school.
Academic advising is available depending on what school you go to. Each school does a really good job of assigning a specific advisor to whatever major you take. At the pre-professional advising office they work with law, medical, dental, and vet. And say, OK, given that this is your timeline, we can figure out when you need to take an exam, what courses you may need.
My experiences with all kinds of advisers have been just very personal and not rushed, I think is the good way of saying it. They take the time to get to know you and to get to know what your problems are, or just what your interests are. They really are looking out for you.