Just saw the OP's question and noted that his flight was this past Saturday. I'll weigh in with some comments for other travelers departing from YQB.

At YQB 45 min before scheduled departure time is usually sufficient, depending on the time of day. You would be OK for a midday flight.

However, depending on your travel dates, you need to consider that YQB has heavy cruise ship rotation traffic with pax heading home, mostly to US destinations via YYZ and YUL, after disembarking at the Port of Quebec.

Cruise season is heaviest in SEPT and OCT (autumn colour cruises on the St. Lawrence and Saguenay).

The lineups at CATSA screening can get long and if you don't have NEXUS to skip the queue, 45 min pre-departure could get tight.