You sound passionate about Williams and since you applied ED, I think you’ll get accepted. Apparently the acceptance rate for the Williams Class of 2020 was 42% ED (246 accepted and 585 applied). Just make sure to also have other apps planned just in case. Best of luck!
Chance me back: http://talk.collegeconfidential.com/what-my-chances/1936788-predict-my-results-stanford-mit-princeton-cmu-and-others.html#latest