did you mean to type 747, or were you thinking 737? The A320 is dwarfed by the 747, but is roughly the same size as the 737.
It may just be a perspective thing that makes it 'look' as though you're a similar size as 747; an in-cockpit view is pretty high up from the tarmac, and depending on what your 'view distance' percentage setting is, it could possibly make the aircraft in front appear smaller than they really are. Just go park your A320 next to a 747 and switch to an outside view...you should get some idea of the sizes!!
And Yep! The iFDG A320 is brilliant