The only one of our three who had an early commitment was our oldest who is now a 3rd year veterinary student. The other son favored some kind of engineering but was essentially undecided the first two years. Our daughter, hopefully, will decide what she wants to do before whatever she selects becomes obsolete. Every university has financial aids and scholarship representatives. Those are usually good people to know.
Financial assistance is often available but takes some effort to find.
There are some helpful sites on the Internet which list scholarships associated with various majors. Your financial aids department can help you with that. For a student who is particulary strong in a given area the CLEP test might be a good investment. How much of an academic load to carry the first semester is a big decision to make. At the same time, be aware that fees over and above tuition are the same for all full time students whether they are taking the maximum or minimum number of hours.