I think you were up front with your quilting skills and price. I however don't think you should have gotten snippy with your customer. It's fine if she didn't do the math herself. (That's why you are there.) But, you did burn a bridge and it may be harder to build a cliental if you receive bad feed back. It would probably have been better to finesse the customer. (Even if she was rude.) It's one of those live and learn things. You did not state, is this a new venture you are going into? (Quilting other's quilts.)
Congrats on having the first customer under your belt. And, it sounds like you learned a bit along the way.