Was I sexually assaulted?

So I’m 18 now but I remember in 8th grade everyday before going to class this guy would wait at the door for me and wait for me to walk into the classroom first and when I would, he would quickly walk behind me and feel me up my ass ._. This happened for weeks and the teacher finally caught it, idk why i didn’t say anything I probably just didn’t want drama but was that sexual assault?