How to I break the news to my mom?

Ok no pun intended and I know this is very low stakes but I’m so upset and I don’t know how to tell my mom.

A few months ago she came to visit me and bought a beautiful, one of a kind, antique stained glass window. She couldn’t safely take it back in her car so she gave it to me for safekeeping until her next visit. She’s been back twice since then and both times I reminded her about the window but she didn’t take it.

Well, the worst has happened. I had it leaned against a wall in a corner of my apartment that doesn’t get used much, in between two cabinets so there was no way someone could accidentally bump into it. I thought it was completely safe there. I just heard a crash and somehow a framed photo I had hanging on THE WALL ACROSS FROM IT fell off, bounced on the floor and smashed directly into the window, wtf 😭

She’s going to be SO disappointed. And it was expensive. I know she probably won’t be mad at me because it was an accident and she left the window here for months but she loved that thing and it was a very special find. I have to tell her what happened and I’m dreading it. I really hate letting people down, especially my family. What do I say 😭

(Yes I know it’s just a window and not the end of the world and “Kim there’s people that are dying” but I feel sick to my stomach about this)