Oh, yes, I know I've got to do my teenage life. But as it takes too much time to get the citizenship, I've got to start thinking now. And yes, I'll stay 4 or 5 years and train personaly. Then, join JTF2
Oh, ok. Just because I'm curious, is the JTF2 the only SOF in the world that is a one-chance, if not you can't join?

You can try for selection as many times as you want. Or at least as many times as would be reasonable for you. If you come close the first time around but just don't make it, then it'd be worth your time to give it another shot after you've had some time to train and gain some more life experience. If you thunder in after one day, then it'd be best for you to take another look at your priorities.

Either way, I wish you the best of luck. And an early welcome to Canada and Her Majesty's Canadian Armed Forces.

As for the US side of SOF, in almost all cases, if you don't pass the training you won't be allowed to come back. The vast majority of cases where they are allowed to come back is because they had to recover from an injury during the training. Most US SOF units have different phases of training though. For instance, to become a SEAL you have to complete BUD/S training which is broken down into 3 phases over 6 months. If you fail phase one(fail not quit) you recycle back to day one. If you complete phase one but fail phase 2 you recycle back to the beginning of phase 2.(failing means not passing just one of the numerous evaluations they administer, if you fail several then you will go before a panel and they will decide if you're going to be dropped or given another chance)

Even after training you must go through another 6 months of rigorous training and are not a bona-Fide SEAL until serving in a team and proving yourself. At any point up to where you're proven it can take over 2 years and you can be given your walking papers at any time....and that's just to be a SEAL. US Army Special Forces has training pipelines that last no less than 18 months and over 3 years if you're a team medic! That's not even stepping foot on a team! Once in a team, again, you must prove yourself during a probationary period and you can be given your walking papers at any time.

One thing is for certain though...if you quit, you can NEVER try again...at least in the US you can't.

Thanks for the answers. I think, with what you've said, I'm gonna prepare for SOF during my 4-year-obligatory service before I join SOF. Going to do my best!

If you have the determination, you will succeed.
Remember to train your brain, because it is as much about mental strength as physical strength. The basic difference between an ordinary man and a warrior is that a warrior takes everything as a challenge while an ordinary man takes everything as a blessing or a curse. So be positive in everything you do and what life offers you. Learn where your boundaries are and when you find them, you will find that you can mentally move them.

Remember, you can do 100 times more than you think and 1000 times more than your mom think you can do.

Now, carry on soldier.