Be prepared that the actual experience of discovering her death may need some coping, too, and be willing to discuss it in detail with your daughter if that’s what she needs. I don’t have experience losing a parent, but I unexpectedly found someone dead a few weeks ago (natural causes) and it was pretty traumatic. I found her dead in bed and have had disturbing flashbacks triggered by simple things like going into a room and finding someone sleeping in a certain position, or not being able to wake them up right away.
That’s awful, I’m so sorry!
My niece and nephews were 15, 14, and 13 when their mother died (actually, it happened on the girl’s 16th birthday.) People are always asking me how they’re doing, and frankly I have to say I don’t know - sometimes you just can’t tell with kids. So I guess that’s my advice - sometimes you don’t always know what’s going on in their heads, and that’s normal.