Working in a factory, my colleagues advised me to wear a skirt to work? Are you laughing at me because I didn't wear a skirt?

If your factory doesn't explicitly prohibit wearing skirts at work, you can wear skirts to work, but it also depends on the weather. If it is too cold in winter to wear skirts, you can wear skirts in summer. Your colleague is not laughing at you, he just wants to see your figure.