For clarity I'm going to use DC's birth pronouns here.
When DD was born I gave her a lovely first name -- the best first name I had ever heard and one I had been saving for a daughter ever since I came across it. It's unusual but not "out there", and has a lot of meaning to me and in general just sounds really lovely.
Last year she came out as a trans boy (along with her entire female peer group, but that's another story). She's struggled with her identity as trans and has questioned whether she really is many times, so I don't think it's likely to stick long term.
Yesterday we were chatting and she said that even if she detransitions she's not going to use her given name again because "it's just not her".
This seems like such a minor issue but it's hit me like a ton of bricks. I'm really gutted (for the record, I didn't tell her this). Am I being unreasonable to feel this way? It's her name after all. I feel like something has been taken away from me, which seems self centred, really. How do I grieve this and move past it?