Getting into a bar/club at midnight of my 19th birthday?!
I live in Toronto by the way.
Answers:
I suspect you will be fine. The main reason why one wouldn't be let in for being underage is because if the bar or club is found to be serving alcohol to minors, they will be fined heavily and risk having their liquor licence taken away if the problem persists.
In your case, you will actually be 19. The bar will not be able to get into trouble for serving you. Therefore I don't think they should have a problem serving you. If a bouncer or waitress questions your ID, just show them the date on your watch or your cell phone and that should suffice. If you still have a problem then just go to the next place. I doubt you'll have any trouble at all. I don't know how Toronto is but when I turned 19, I was rarely ID'd.
Have fun!!
If you know some of the places you'll be going, try calling ahead and asking. No harm in that, and could save some time and frustration.
And Happy Birthday!
I think you should be okay to drink as the date does change at midnight. Happy bday and drink up!!!!