I'm not sure if that term is offensive or not, forgive me if it is. I have an idea of what it means though, a lesbian who has never been with a man. What I don't understand is, is it talking about sexually or romantically? Like, if a woman has dated a man but never had any intimate activity with them, and vice versa, are they still a gold star lesbian?
A gold star, to my understanding, is based on if you've had sex with a man or not. I dated a guy when I was 14. Never slept with him or did anything sexual with him. So I'm gold star according to how I understand it. Be aware some people do find the term offensive or "elitist." I just find it fun.
There is also "lone star" which refers to someone who has only had sex with one person for their entire life.