Here is how to dress when you're in your 3rd decade. (20 to 30 years of life.)
Find something that is comfortable to wear for 10 hours non stop.
Be aware that your clothing will present you to the public as you are dressed, not only how you desire to be presented. This may be as simple as sweat pants and a T-shirt, or as complicated as at 3 piece dress suit.
Dress in something comfortable, yet socially presentable.
Wear it for a day, and observe social reactions
If there are no negative social reactions, keep the same standard in mind, but try variations of your attire.
Once you have settled on a socially acceptable attire, and a comfortable dress, wear the garb to work, and enjoy yourself!