Having some trouble starting this story, help please?

Write anything, and just keep going. My first chapter is now my third chapter and the first paragraph has changed ten times.
I know it's redundant, but just write, and worry about it later.

Write the first chapter both ways, and maybe the second, see which one you prefer more. Than keep going with the preferred one. If you decide you don't like it by the end thats why you have rewrites.

For what it's worth, teaser scenes where you show something later in the story and then work up to it almost never work. The scene is usually exciting only if you know the characters and why they're in danger, and until you know that there's no reason to care. Everything is happening without context. Then, there's not a lot of tension because you already know what happens, so readers are just reading until they get "caught up."

I'd suggest starting just before the event that gets your characters into trouble, whatever that is. It doesn't have to be the major story problem, but an early step that leads to that. Something that introduces the characters, offers a problem/mystery/question that readers want to know the answer to, and then work toward how that gets messed up and sets up the rest of the book.

Maybe start just before things get weird and creepy. If the dilemma is childish, you probably want something that isn't If you don't have any respect for it, you can't expect readers to. Unless you meant that they're having a childish problem, as in "that was so silly for us to be arguing over" type thing right before things get weird.