OP. you CAN change the college that you list as “first choice” numerous times.
HOWEVER, I believe that colleges KNOW this.
So dont try to play the game- WAIT to designate your “first choice” college until you decide where you want to enroll., i.e. in May.
That is when NMSF sends the FINAL first choice lists to colleges, who match lists of who have accepted offers of admission to NMSF lists.