you know....even though I do agree this is not a good thing and the pup is too young, I think you all are way to harsh, and judgemental. I have noticed by browsing this boards for a year that you have to walk on egg shells about what you say or get chasitsed.
they way I read her post was that she didn't breed them and that she did have them apart but the children didn't understand "heat" and are probally use to them playing together as puppies so didn't know not to let them together, accidents happen, even with people. I'm sure a 15 yr old teen age girls mother feels bad enough if she got PG and needed advice without having to be treated like she just comitted a murder!
well, I think her question is it happend (so the advice of spaying right now is usless till pups are here) and telling her after the fact that her dog WILL die is pretty cruel too.
So here is my advice for what is is worth, friend...
It is sad it happened and I'm sure you regret it, but it did...so go to your vet and tell them and they will keep a close watch on her through the pregancy and all you can do is hope and pray for the best, but, she will most likley be ok, dogs in the wild don't know to lay off their first heat. good luck