Every time I start a project I ask myself that question and then do the very best I can. I give my quilts to friends and family and, they may just be being nice, seem to love my work. If you do the very best job you can, pay attention to the little details and people remark how beautiful your work it then you are definitely "good enough." I'd bet you are a terrific quilter, the fact that you would even question yourself should tell you how much you care about what you make.