What age is appropriate to accompany putting down a dog.

I really wish I didn’t have to ask this, but I think the time has come. Our sweet, old dog has severely worsened and I’m trying to be prepared for the end. We have an almost 4 year old girl that loves this dog dearly. She knows he’s not well, knows what death is, etc. Should she be with us and him at the end? Does she stay with someone and we just tell her later? I’d appreciate any advice, including what to tell her if she doesn’t accompany us. Thanks. via /r/Parenting http://bit.ly/2QkvJdf