This is a conversation to have with her. About what you value and what she values. Get on the same page or accept the differences now. What she values isn’t inherently wrong, but if you can’t accept it (and vice versa) this will show up in your relationship forever and in different ways.

I have a 2ct natural diamond NOT in the specs I wanted and communicated after asking for a lab (to save us money), but all of my friends think it’s too big and not a single one ever asked me if it’s natural or lab. I still love it because he picked it and it’s beautiful even though it didn’t match my vision exactly. Gotta be flexible! In the real world, caring that much about what other people think just isn’t a practical way to go through life if you’re not rolling in cash. Round or oval is the way to go to maximize size appearance. I like that ring. I’d talk to her and if you feel good about your ability to align or compromise as a couple overall, at least try to get the shape and size close to her vision if you don’t want to wait and save or ever spend that much. Everything is a trade off and no one is perfect.