i'm 5'5" and a size 10 on average, but I have some muscle and am pretty curvy.
I've seen girls our height who look good at size 0 and ones who look good at size 16. It's all about your bone structure, muscle, where your body carried fat, proportions etc.
also, some guys like petite girls and some like thicker, so you need to figure out what size you feel most comfortable at, what size you feel healthiest at, and what size you like the way you look the most.
As it stands, you're too short to have a size. According to the Barre-Attley Associative Height Chart, a woman must stand at least 5' 6" tall to be issued a weight ratio. Being as you're 5.479 feet in height, and if you should unexpectedly break wind you'd easily drop 0.012 inches, you'd be best advised to consider taking a position as statuesque mid-level primate.