My advice would be to not freak out over it.
You'll learn by trial and error and practice and seeing what works best for you and your machine. If you want your quilt to be perfect, make that as a goal, but not a goal that is set in cement. It's ok if things don't match up perfectly. It helps if they do, or if you intend to compete with your quilts. This process should be about relaxing and fun to do and not to stress out over. There are a lot of different ways to achieve a 1/4" seam so try out the different ways to do this and pick one that you like best.