Being an OTR right after training?

Not sure about Canada regulations, but in the USA there is an exception for driving interstate if you are hauling farm equipment. There's a couple of members of the forum that got started driving at 18 y.o. by getting on with companies that haul harvesting equipment, following the harvest from Texas on up to North Dakota. It may be the same in Canada.

You can get your CDL at 18 in the USA, but can only drive intrastate until you're 21. Most trucking companies won't hire you for OTR until you are 23 because of insurance. Insuring a driver under 23 is very expensive.

There's been other threads about how to get into professional driving when you are young. Seems that most folks are recommending hiring on at a warehouse, get your CDL and be available to spot trailers or take short hauls as the company might need. Oil fields in Canada might have a few companies that could take on a younger driver. The thing is you'll need to do your own research with the regulations in the province you live in and Canada regulations, then you'll need to start getting on the phone or visiting trucking companies in person and talking to the folks to see what might be available.

OTR will HAVE to wait until you are 21 (unless you are working agriculture but not sure about this in Canada) and certainly driving between countries will have to wait. You might have to wait until you are 23 to be hirable by an OTR company. Note that when you get OTR you will be able to deliver loads from Canada to the USA, or pick up loads from the USA delivering in Canada, but you won't be able to take loads that pick up AND deliver in the USA.

 

there is a Canadian forum on here;

http://www.thetruckersreport.com/truckingindustryforum/canadian-truckers-forum/

you could get better answers there, I would imagine.