Could I join the Canadian army without anyone finding out I'm trans? Or is there some way they would find out?

If by "anyone" you really mean "anyone," then no. There'll be a mandatory physical exam and a background check, both of which will out you, and a medical history questionnaire that you'll be legally required to answer truthfully.

If by "anyone" you mean "the people I'm going to live and work with," then likely yes, but you should talk to a recruiter about it. Tell them your situation - you'll have to out yourself during the enlistment process anyway, so might as well out yourself to the recruiter early and get all the information you can.

Ok. So they would proably find out. Would I have to deal with bullying (Canadian army)? Sorry for all these questions but sometimes I feel like it's my dream to join the army and I'm worried that I may not be able to because of this.

There are policies in place against discrimination, harassment, and bullying. Whether they're 100% effective I can't say (I find it doubtful) but they exist, and there is a system for reporting offenses.

thanks again kyril