Ooooooo... a Blue Seventy. Nice suit!
If there are no wrinkles when it's on, then you're probably fine. If it fits tight and smooth, you're probably OK. If it's at all loose or has lots of extra "bulging" when dry, it will probably be too big once wet.

I'm sure yours will be fine! As petite and tiny as you are, a small is probably a good size. I wouldn't worry... but then again, I'm not the one who bought the new suit and will be stuck with it if it doesn't fit.

I say, take the leap, pull the tags and jump in the pool with it on. If all else fails, can you could sell it on eBay- and probably get the same amount you paid for it since it's new with tags. I got almost twice what I initially paid for my older wetsuit when I sold it recently on ebay (bought it for $15, sold it for $25), and it was VERY used. I've seen new suits on ebay go for quite a chunk.