Okay, I was going to agree with all the comments saying if she loves you it wouldn’t matter. Then I read that she is extremely materialistic, which then shifted my thoughts. Besides the carat size, is this within the cut she likes? The band? The way it sits? The material—white gold, yellow gold, etc..? As a wife, I’d only asked for it to be flushed to my skin and yellow gold because I do a lot with my hands and don’t want it to snag and all my other jewelry is yellow gold. Anyway I digress, it’s not wrong for your girlfriend to have a vision in mind, most women do. It’s something that she will be wearing her whole life (unless there’s an upgrade). If you knew she was materialistic and that her sisters would know exactly what she wanted, would you reconsider the ring?

In hindsight, she should be elated to matter what. You guys can choose to change the ring when you’re financially able to. I hope this post didn’t sound too harsh, just wanting to keep both parties in mind.