Why is my waist size so high compared to my weight?

Ok so i wanna make a dress for myself and i took my waist measurement and im about 39"! But then i read that 24" is quite normal so im freaking out. I fit an english size 12 (american size 8), am 5ft 1 and weigh 141 ilbs. I'm aware this is kind of overweight but not majorly so why is my waste size so much higher than average? Whats wrong with me? Did a measure in the wrong place or what?