Well, what is an internship? Post internship? I think if you practice in that office, please invite your colleagues in that office. If there is a leader above, it is the top leader of the bureau team and the office staff. Your birthday is mainly to let everyone have fun. Don't think too much. This is not an important part of your relationship. If you really feel that you haven't done anything, do it well, then you won't be happy and there is no point in celebrating your birthday. Why not?