also---start small- and work your way up to that large quilt- don't think you can make a couple 12" pot holders look pretty good so you are ready to now do your queen size quilt.
practice on that 12" square- when that is looking pretty good- and you are feeling confident- move up to maybe a 24-30" piece---then a bit bigger and a bit bigger- each larger size will have it's own set of (issues) new feeling-new things to deal with (like handling that bulk in the throat of the machine- and the weight on the outside---it all takes practice and more practice- not many are fortunate enough to just (get it) and be able to sit down to their machine and quilt a large quilt without having spent many many hours of practicing to get to that size successfully