She could have ordered it as motivation to lose weight.

Because ordering something to motivate you to lose weight for prom is smart! :D

YDI for buying a dress that took you five years of weight loss to fit into. But congratulations. Perhaps set the bar a little lower next time

30, it could've only been 10 pounds but she starts working out/dieting then loses motivation and stops (like most people do). That would explain why it's been 5 years (even though it's an off and on thing).

So true!! Not many people can say they look better (or thinner or more in shape) 5 years after high school than when they were actually in high school! I'd give anything to have the same body I had in high school, never mind an even better one!

I'd use the words "are healthier now" instead

People do it all the time. While it might not be the smartest idea, it serves as inspiration. That way you know what you want to look like, how much weight you need to lose and then you work to achieve said goal.

It's definitely not smart because you can't know how good or bad something will look on you until you can actually put it on properly. She could have gone to all that effort to lose weight to fit into a dress and found out that once she was wearing it made her look like a clown. Never buy close to motivate weight loss.

She could've bought the dress online in the size she usually wears, but it didn't fit her right. A lot of people are different sizes in different stores. They may take a 8 in store A and a 10 in store B even though they haven't changed weight. Not all stores have exact same sizes, especially if it's a small, medium, large thing.

That wouldn't explain why she didn't just take it to be let out a bit if that was the issue. If the difference in size was only the effect of different companies sizing than that would have totally been an option and she could have already fit into the dress and worn it to her prom. The fact that the OP says she can "Finally" fit in it really makes it sound like she intentionally ordered the dress too small on the hopes that she would be able to work down to it. It generally costs less to get an existing dress tailored a bit to have it fit you because its a bit small than it does to by an entirely different dress to replace the one that doesn't fit.