First of all. Be READY TO WORK! Music Majors have around 10 to 12 classes with only 18 hours of credit. On top that, you have to practice outside of class on your primary and secondary instruments (voice, piano, brass instruments etc.).
Also, start looking up some information on Music Theory. It is good that you can read music, but learning more in depth theory will enhance it as well.
I know these things because I am currently a music major holding a 3.94 GPA.
If you have anymore questions, feel free to ask or PM me.