If I were you, I'd want to tell your sister—for her own sake, and the sake of your relationship. Imagine how she'll feel if she does find out one day, and learns that you knew and kept it from her as well.
The Ontario Provincial Police arrested and charged 36 men in a child sexual exploitation investigation, reflecting a growing concern over online safety for children.
I think I'd want to start by having some honest conversations with your kid about what's going on at home, without focusing on the question of whether or not you'll go back.
"People often really don't care about your new baby. They're just asking you about your baby because they want an opportunity to talk about theirs. Their kid might be 15, but they want to tell you stories about when she was a newborn. You make their day when you humor them!" - lisafatgirlnamemcquade
If you want to offer an explanation, let your family members know after the trip that in an attempt to preserve the surprise for your children, you waited until you were already on the way before telling them... I'm sure some family will say that they would have gone if you'd told them, or that they wish they could have been there at the same time, to which you can express your own "regret" and say, "Yeah, maybe next time."
