I dropped an online course..will I still be able to get into University?

I live in Canada, ontario. I already graduated highschool and recieved my highschool diploma. The thing is I needed to take certain courses to get into the program I wanted for University. I took 3 online courses, and Ive already got accepted into University because I sent them my midterm marks from those 3 online courses. QUESTION IS: since Im already accepted into University, can I just drop those 3 online courses? I mean, on my acceptance letter, they didn't say I have to maintain a certain mark or whatever. They just said Im acceptance because ive reached the average admission mark on my transcript.