[ Singles & Dating ] Open Question : My girlfriend wants me to talk to their parents?

ok, well me and my girlfriend have been going out for 4 months now, but their parents dont know this. I have seen and talk to her parents, but her parents know me as her friend. My girlfriend said its time to tell her parents about us, that we have a relationship. But i dont know what to say, i cant mess this up.. i only have one chance to say everything perfect.. Anyone have ideas of what i can tell her parents?