I'm scared to enter my horse in an event. HELP!?

I got a beautiful bay gelding thoroughbred for my 18th birthday from my dad I love him so much his show name is Calm Before The Storm but his stable name is Callie, I love him so much when I first got him he was nervous around me but I was show how to use this Join-Up technique by one of the instructors that work at the Equestrian centre were his boarded and it work amazingly he trust me fully when I go to visit or ride him he always seems to know I'm coming and calls out to me and looks so happy. I always bring him a treat though. He is so amazing to ride and really listens to me. But anyway we've just finish learning to show jump and we were invited to enter a local show jumping comp by the stables. He loves to jump but a week ago one of the horses at the stables being used in a jumping lesson crashed through the jump and broke his cannon bone it was so bad he had to be put down. And the jump was the same levels that we were riding. It tried to jump over but his front leg got caught on the pole and he fell forward and the weight of his body pushed his leg down onto the fallen pole. I knew that horse and he was amazing the rider was devastated but now I'm to scared that something will happen to Callie and I'll lose him. HELP