NWT size 4 Ivory wrap Romper/ Playsuit

Super cute & flattering white Romper in size small/medium the tag says size 4, i am always right in between so its hard for me to guess my size in some clothes- I'm so bummed because I thought this was an 8 cause i wasnt paying attention so i bought this & surprise! (no surprise)- it didn't fit me so im reposhing it! it's so dang cute tho so I'm looking for a similar in a bit larger size I guess like 6-8. I'm 5'4" 136lbs & size 36C up top fyi.