Not taking class listed on Common App "current courses."

During second semester of senior year, I listed that I would take 4 community college classes (2 per quarter). Each quarter is half of a high school semester.

I just realized however that the 2 other classes I plan to take might not be available when I go to sign up (high schoolers don’t get priority registration, and they are popular classes). Regardless, I’m going to take 4 classes, but if I get admitted and take a class instead of the one I listed on my application, will that be cause for rejection? Should I email the colleges about this potential issue now?

Do not worry about this.