Dress

So I had been looking at this dress for homecoming arpund the time of the dance but it was $120 and I couldn't afford it with my own money. Today I saw the dress again but it was on sale for $20 and they were getting rid of them soon to make room for new dresses during homecoming season- so I bought it. I'm normally a size 1, and that's the only size they had left. I'm afraid the dress is too small or will be too small by the time of the dance. It has a corset thing in the back so I can get it in perfectly fine. I'm just afraid it won't fit. Should I take it back?