This is good advice. My Mom left my sister and I a few UFOs (Un-Finished Objects). So far, we put one together. In the process, we found out why it was a UFO! I think it was one of her early efforts - cutting was terrible and the blocks were sewn, well, like my first blocks were sewn! My sister adjusted some of the blocks, but left the majority of them 'as is' and sewed them together. While quilting it, I had to make a few more adjustments to them. Nonetheless, it turned out very pretty and gets lots of compliments. One of her 'grands' will eventually get it and they won't care about the imperfections.
Long story short, first learn the quilting craft, then tackle the UFOs. I would not have known how to modify that little quilt 5 years ago...so would have destroyed it.