Feline Fanatic summed up the situation very nicely and as others also stated gave you exact figures to present to your customer. I completely support that you should not be the only one learnng a valuable lesson through this. Have you checked the websites of others in your general area who do quilting professionally? (And yes you are now officially a professional). Having a few of their going rates as examples if she questions the figures would help. As for your quilting not being that good? Let me just say I aspire to someday--Someday being able to quilt feathers like that!