As long as you stick to patterns or designs that are more 'free flowing' and don't have to fit together perfectly at seams or points, I say what you are doing is fine--especially if you like the results. There are a lot of modern quilts that are very spontaneous and fluid, the design rests more in the color/value choices rather than a fixed geometric designs. Just don't pick a pattern/design that requires exact cutting and sewing, or you might get really frustrated trying to put it together. That is what is nice about quilting, there is something for everyone!