In my opinion being a Valedictorian is better than not being valedictorian, however, remember there are some 20,000 high schools and many of those will have multiples of students who are excellent candidates for admission to top universities. Yale will eventually matriculate around 1300 freshman and probably accept double that. Check Yale’s common data set to determine how important class rank is and that will give you an idea of how they view it. Yale is a reach for you as it’s a reach for anyone. If you wish to have an opportunity to attend then by all means apply but don’t make attending Yale your end goal.