I'm sorry I am not knowledgeable with this, but I really hope you do not cross 19 before your mom get's the visa. See here: http://www.cic.gc.ca/english/department/media/notices/2014-06-23.asp
From the above link it seems to be that previously you needed to be a full time student if you were above 19, but now it does not matter i.e. you will not be eligible. So I think you can interrupt your studies. However, that's just my opinion. I hope some seniors can respond to you.