I have to second what pumper said. In my community, I have no yetzer hora to wear short skirts because it’s completely unacceptable here. I would be the odd one out and definitely feel out of place. When you’re in an environment where “everyone does it”, it’s that much harder. It’s not so simple to pick up and leave your neighborhood, job, etc., so it takes a tremendous amount of resolve to make a change like that. I give you credit for taking the first step, having the ratzon to change, and I wish you much hatzlacha in succeeding in this. You do have the koach to do it–and it will get easier with time if you keep at it.
Popa–Most women can’t wear the same clothing at 16 and at 26. Firstly, things goes out of style (and there’s nothing wrong with dressing in style, as long as it’s not a tznius problem). Second, as other posters wrote, women’s bodies change. Tops are suddenly too fitted when they were never a problem before, skirts become too tight, etc. A few kids down the line, very few women can still fit into their sheva brachos clothing.