Anything new and unknown can be scary at first, we all deal with that. Luckily, your child has a few things going for them, they have you, a loving God, and leaders who care about them. All these people are encouraging them, guiding them, and cheering them on through new things since they know they will be stronger because of it.
You know them best and they trust you, that's why your words will have more power than you may realize. This is your chance as the parents to build them up with words of encouragement and excitement, helping them to realize that they are strong and with their Heavenly Father by their side they won't be alone. Talk about how excited you are for them to have this experience and how many amazing memories and friends they're going to make.
Another great way to help encourage them is to let them know that this will feel like a really cool sleepover and reference some of the fun times they have had camping or at sleepovers before. If they haven't had sleepovers before, then this is the perfect time to have some! Start with a family member or a really close friend and give your kid a chance to get out of the house and experience some fun in a new way. The more sleepovers they have the more comfortable they will be going to camp.
Another great way to help your child feel comfortable is to invite a friend or cousin to join them at camp. This is great way to invite someone who hasn't been to church before, but it's also a great way to have an instant camp best-friend already built in.
Talk about camp often and bring stories in as much as possible. This will build the best anticipation in them. Think about your favorite movie or vacation and how your anticipation built every time you talked about it with someone or thought through what it would be like. Your kids are the same and the more they hear and talk about it the more they will lead with anticipation!