hi!
I believe you would have to be 20 by the time of the application.
i went to an assesment with a girl last may in toronto. and she succesfully made it to the final interviews and everything. all she really needed was to wait for her offer. 2 weeks into the waiting period she got an email from them and instead of an offer she got a "we are no longer going ahead with your applications"
she was a really good candidate but when she called to double check on why she didnt get it..she was told that basically she needed to be 20 and to try the next time theyre in town. (her bday is in august)
hope that helped.
good luck