Too racy for homecoming?

So, I found a dress online that I am absolutely in love with!! It is the exact blush color I want, has some really cute trendy features and has sleeves that go to the elbow. It is loose fitted and overall very classy... except for the length... The dress is 30.5" long (Size small) and appears too short for my mom to possibly approve of. The model is 5'7 and I am 5'5. Will that make the appear more appropriate on my than the model. My measurements (Waist, bust, etc...) all suggest that I should get a small, but maybe a medium would be a better route, my only fear is that if I got it a size big it might look like a garbage bag. Does it look like it could be tailored? Please help because I really do love this dress.
http://www.tobi.com/product/51779-tobi-ever-so-scalloply-dress?color_id=70136