I want to chase after her, but I'm afraid my colleagues will laugh at me when they see it. What should I do?

Personal suggestion: first secretly observe whether she has feelings for you. If she has feelings for you, you can launch an offensive and let her know that you are good to her. For example, if she is in trouble, give her a gift on holidays or something, and you can also use some pick-up routines appropriately. Finally, find a suitable time to make a romantic confession through some of her performances, and this is done. Of course, all this is on the premise that she doesn't have a boyfriend.