Additional Info Section

Hi all, I am a student from an international school system (in the USA) applying to some top-tier colleges. As my situation is a bit unique considering my school system, I decided to take advantage of the additional information section of the common app to write the following (along with some other things):
“A note on extracurricular activities: I believe it is important to note that my school system is extremely rigorous and takes up a good amount of my free time. For example, I have school from 8:30 AM to 5:30 PM, and teachers typically give many hours of homework. Additionally, I have decided to take the most challenging courses offered, which therefore require more hours of study. In consequence of all this, I do not have time for as many extracurricular activities as I would have wanted, and I might have less than my American counterparts.”
Obviously, my application has already been submitted, and everything I wrote is true, but I am suddenly second-guessing myself. What if admission officers find me arrogant? My point in including this info (which I don’t know if the counselor has already included it in her letter) was to avoid having college admissions officers saying “oh, this kid has less extracurriculars than this other kid [who probably finishes school at 2:30 every day], we’re not going to admit”. Now, however, I don’t know anymore if it was a good idea to include this information. What do you think?