Make sure she's home, she can either watch or not, her choice. But do what's best for YOUR horse before listening to an emotional, irrational 12 year old on the subject (I'm not meaning that as a snotty comment, but I know that's a really tough age when hormones go nuts is what I'm trying to say... I remember being that age.) If the horse is ready to go and obviously going downhill, it's time to say goodbye. Your daughter will understand that sooner or later, and if she doesn't, well that's for her to deal with in her own mind. Losing a horse hurts like heck, I'll be the first to say that, but when it's time, it's time. By twelve she's old enough to understand death and that it's nicer to put the mare out of her misery than make her suffer forever just so she (dd) can be happy to still have the horse around. That's just my opinion, I'm not good at wording things, but I tried lol. Really sorry about your mare, I know that's a tough decision.