I think your quilt is great. Using inexpensive shirts is a great idea for trying our something new. I am a penny pincher and don't like to use expensive fabric for "experiments" or trial and error, so I like your idea of using inexpensive fabrics for this type of project. I have learned over the years that my enthusiasm often exceeds my skill and have ruined plenty of expensive fabrics by diving into a project without practicing first. If I could go back I would have done them with "practice" fabrics and taken the time to do some trial blocks. Congrats on your new quilt!