We all started small....I had a corner of the living room, too. Finally got a closet to myself when we built this house! The reason I now have a separate studio is because as the boys moved out, I took over space. My husband was afraid I'd push him out, so he closed off the carport.
Your room is really very nice. Can you call yourself a newbie if you have a dedicated sewing room? I say you're past newbie stage....at least in the hooked stage. As for stash building, don't rush it....it's part of the fun!