Sometimes you hear people who say "from the time I was 6 I knew I would be a(n) _______ [doctor, astronaut, researcher, dancer, singer, rancher, etc],", and they are now an adult and they are exactly that. They never wavered and they're very prominent in their field and satisfied with their lives.
However, a large percentage of happy and functioning adults don't enter college knowing precisely what they plan to do as a job or career.
College is more than choosing a major and sticking to it. In college, a student may encounter a professor who introduces that student to a field the student never knew existed before. The student may meet another student, perhaps from a different country or different circumstances in life, who makes a profound impact on the student and changes the student's future. College teaches a student about the world, about his or herself, and about the opportunities that exist out there.
Many, many students change their minds about their majors after exploring an introductory course in another subject, or after talking with an advisor or professor. This is the time to learn about your strengths, your goals, your interests, your passions, your weaknesses, your abilities. Encourage your daughter to explore, but to do her best in every course that she takes. She may have to take core classes in something that seems irrelevant to her, but studying produces discipline and development and growth. Encourage her to do her best work in every class, and to approach them all with an open mind and a receptive attitude. She may discover that she has a passion and skill for medicine, or cancer research, or teaching, or music. Or she may continue in computer sciences and proceed along that path.
And trust her advisors and professors to guide her. Professors and employers and mentors look for character, reliability, dedication, attitude. They're ok with changing majors. If you asked someone who is successful in a demanding career, they'd be very likely to say something like "I started out planning to be a guitarist [or a dancer or a pro football player or a nurse] and in my junior year I met a teacher who helped guide me towards becoming the [astrophysicist, percussionist, kindergarten teacher] that I am today."
Help your daughter be excited about all that college offers, and don't worry for a second about changing majors during her first few semesters. The time to worry about changing majors is when they're a senior, 1 credit away from graduating, and they tell you they think that a degree is pointless and maybe they'll backpack through Australia for awhile. Then you worry.