I believe I read this book in the 90's. I doubt the book was published much past 1999.
I believe the protagonist is a female character who might be a stowaway on some kind of intergalactic vessel. I don't remember how she got there.
The bulk of what I remember involves the girl overhearing a conversation between different alien species representatives on what should be done with Earth now that Earth was exploring more of space. Some of the aliens wanted to destroy Earth before aliens were discovered and war inevitably broke out. Some wanted to preemptively contact Earth and try to make peaceful relationships.
The girl was shocked by these conversations and I believe she may have inserted herself into the conversation at some point. It's possible this is a short story, but I think it was in a novel.