My family room is 15 x 24 feet and I would die to have a room that big to sew in. It is definitely large enough to accommodate the items that you mentioned and leave plenty of extra room for shelving and a stash.
In my family room I have a good sized couch, an ottoman, a lazy boy, a computer work station, 2 rocking chairs, an entertainment center, a sofa table, 2 end tables, a floor to ceiling bookcase and lots of miscellaneous stuff. Unless you become a professional quilter, I sure do think that your plan would be adequate.