Accepted to one school but still waiting on another decision with an impending deadline...help?

[myrmidonqueen]

Hey everyone! I was accepted into my second choice school yesterday, UOttawa for a Master in Information Studies. I'm very excited!

However, I'm still waiting on a response from McGill, which is my first choice, for the same program. I emailed them a while back to inquire about the status of my application and I was told they had already sent out their first round of admissions and will be sending out about 50 more mid-April, so I guess I'm on some kind of waitlist since I wasn't outright rejected - but Ottawa needs to me accept or decline their offer by April 14, and I don't know for sure whether or not McGill would have gotten back to me by then.

My question is, should I ask UOttawa for an extension on the decision deadline, or should I email McGill and explain to them the situation, and see if they can assess my application a bit more quickly? I'm leaning towards the latter, but I figured it would be good to get some second opinions. Thank you guys!