When planning a large project it can be as well to start off with a small test piece to make sure you like what you are going to do. Making a large quilt can be both costly and time consuming and you need to be sure you are going to enjoy your sewing.
Try the design of patchwork and see if you like both constructing it and the finished result. Modify you ideas if need be to achieve your goal.
When you are ready to start your quilt you would be wise to work out exactly how much patchwork fabric you are going to use and buy that fabric to avoid disappointment later on. The fabric manufacturers bring out new designs the whole time but many patchwork fabrics are around for a relatively short while and once they are gone it can be difficult and disappointing if you are halfway through a project.