Is it okay for an entry level developer to negotiate for an offer?

I am about to graduate next week and a company is getting the paperwork at the moment to give me an offer. I have seem multiple people say that I should counter offer in some way, but my family says that because I am an entry level, I can't negotiate because I haven't 'proven' myself even though the company has seen all of my work and said that it is very impressive and 'speaks volumes' on my as a developer. Is it common/okay to negotiate an offer if I am presented one?