I don't know how I'll help others as a therapist if I don't even believe in it. How strange huh?
Oh for real, you don't? What kind of help do you want to provide others?
I want to help people relieve their stress.
It's good to want to help others, buy you won't be very effective if you don't believe in what you're doing. Find a professor you're comfortable with and talk it out before you commit to something you're not cut out for.
I'll brush it off and get right to it.
Your beliefs might change if you see progress in your clients. You should believe in what you do from the get go though too, and not just get into the career because of the pay. Be sure you are 100% happy with your career choices.