if you can, i would try to find a retailer around that sells dakine and try them on. if not, maybe email them and see if they can get you that information.
although at 5'3 medium would probably be a good bet. they only go up to xl and you are definitely on the smaller side of the size chart
another option would be to order through evo/backcountry (or any place that has a really good return policy). either get both and keep the one that fits the best and return the other one, or guess your size and exchange it if you want a different one (if you can "borrow" the cash for like two weeks option 1 is normally a really good way to go). you might get stuck with like $10 for return shipping but you get the jacket that fits best that way