Buyer's Remorse

The brunette twin outgrew her winter coat recently, which shold be an easy thing to replace.  After all, it's winter in Chicago, so we're all still wearing winter coats.  In the retail cycle, it's bathing suit season.  All the winter coats have already been on the clearance racks for weeks now.
I went to four different stores before I started wandering our local mall trying to come up with a solution.  I was walking by a store calle Forever 21 when I saw a rack of winter coats on clearance.  I picked up a petite small short wool coat with a hood and realized it might fit the brunette twin.  A woman and her daughter walked by at the same time.  I said to the woman, "This is an odd question, but would it be okay if your daughter tries on this coat?  She about the same size as my daughter."  The girl tried on the coat and it fit.
The price tag made me really happy.  The coat was about $35 full price.  It was on sale for $22.  I was really happy with the price, the fit, the color, everything.  When I made it to the cash register, the clerk said, "Oh, this is such a good deal."  I agreed.  She then said, "that will be $11.99." 
Yes, the coat was 50% off the sale price, plus tax.  It was such a good deal. 
The brunette twin looked so cute in the coat.  She loved it and didn't want to take it off.  It wasn't until I saw her in it that I had buyer's remorse.  I realized she wouldn't be able to wear much more than just the rest of this winter.  By next year it would be too small on her.  I should have bought a petite medium.