I think it would really depend on how fast your bump grows, since everyone's different, i'm 20 weeks pregnant with twins and if I wear a baggy zip-up fleece or sweatshirt you can't really tell
heya. i wasent showing at all at 19wks. i started getting a bump at 22wks and got a proper bump at 28wks. i thought i would be massive at 5months. a baggy dress/top should cover it!