I am very similar to you. I often ask my daughter for advice with colors and patterns because she is much more artistic and creative than I am. My quilts have been mostly my designs but she helps out with colors and placement. For me, the enjoyment is in the sewing and looking at the finished work. I have seen lots of quilts out there that are much more gorgeous than anything I have created but planning, cutting, and sewing for me is very relaxing and enjoyable. It's the one thing I can do that others around me aren't "experts" in and telling me how I should do it differently (I have too many of that type of person in my life!). I think you should use your own ideas, make it your own even if it's not as beautiful in your eyes as your sister's design. At least it will be yours and yours alone and your sense of accomplishment will be much greater. In the end you may decide you like what you did better than you expected!