"Several prophecy writers"
Who are these supposed "prophecy writers," and why should I care what they write?
"assume that all (or most) children will be raptured."
So, you too, are leaving room in your beliefs for children to be sent to eternal torment in hell? Nice.
"I'm unfamiliar with any scripture that speaks to this. Could anyone enlighten me?"
There is none. Nothing in the Bible says anything about children in regard to the rapture.
"As a Mom I definitely want to trust God on this subject,"
Don't you mean "As an ignorant, powerless person, I want to believe there is a benevolent diety ready to bail me out when things get tough?"
"but every once and awhile it creeps into the back of my mind."
Yeah, religious beliefs sometimes give me the creeps, too.
"I know it's just Satan trying to distract me from proper focus."
I do agree that you lack proper focus, but start again. Gather good, credible evidence and do some critical thinking. Feeling any better?