I also love to buy fabrics. They are so fun to play with and stroke. But, if you are going to really make a first quilt. Find a patten you just love and buy the fabrics to make that one. That way you will have a focus.
You see, you stash will grow as you have left overs or see something you can't live without. But, the process of making a quilt, for me, starts with a great pattern I want to make.