There's nothing wrong with wanting to lose weight so long as you're doing it for you and not to please society, but why not work on your confidence at the same time? People who are overweight and have low self esteem think "oh everything will be better if I lose weight", but the self esteem issues won't all dissipate when you lose weight. A lot of people still feel fat even though they're down to a size that wouldn't be considered fat by most people, because they never developed any confidence.

You can wear cute clothes like that at just about any size. Why not go for it now? Look in the mirror and tell yourself that you're beautiful as you are now. That doesn't mean you can't go ahead and work on losing weight, too, but it'll make you so much happier if you build confidence along with it.