Didn't try petite
The heart version is very pretty, i can't speak for the striped one as i have not seen that one in person. i ordered the xxs after trying on the xs, as i felt the petite would be perhaps too short. the xs was a little big on me. the only problem with xxs regular is the sleeves are longer on me, like 3/4 length, not to elbow as shown on model. but i don't want the shirt to be too short so sticking with that size.

for reference, i am 115 lbs, 30dd chest, 26.5 in waist, and short.