Just to add more to DJ's point.
If your younger, 18-19, it might be worth assessing yourself and thinking - Have I got experience in working in a team, have I had any tastes of leadership. CTC are looking for potential, not for you to have done all of those things. DJ and I met a guy there that said in his interview, I have not led a team but I feel I am prepared to do so.
It's a great experience to go through, really gets you thinking about the airline industry as a whole and what being an F/O entails. Just make sure your ready before you do it as you might not get another chance if you fail.