Well at least now you can trade in the ring for a full suit of Halo armor! (I hope somebody gets this reference)

Then pretend she's not your girlfriend anymore

Wtf

When I was 16 my first boyfriend, who I'd only been dating a couple weeks, casually dropped into conversation that he wanted to marry me. He said this while we were in the middle of a crosswalk, and I was left completely speechless, because he was an exchange student who was leaving the country in another week or so, and before this we had agreed that the best thing to do was break up when he left. When I asked if he was joking, all he would say is, "Well, you know, if some day our paths cross and you're single and I'm single..." That sounded too serious for my taste, so I pretended the whole thing hadn't happened. By the way, three years later we did get married, oddly enough.

She probably wasn't ready and didn't know how to say no without hurting your feelings don't take it seriously or break-up with her

not a good day

So when you explained that you were serious did she say yes?

In most cases, I would ask what her problem was. Given your response, I bet you've done stuff like fake proposing as a joke. If that is the case, you deserve it. My fiance and I joke around a lot. Thankfully, if either of us does a joke that goes too far, we talk about it and end it. Nothing is more important than both of us being comfortable and happy, and we are! Also, the follow-up never said if she said yes. Misunderstandings happen, I hope it wasn't enough to change anything.