HIA, I learnt about the I statements in effective parenting training, and my first thought was this should be compulsory learning in high school world wide. I think if everyone learnt how to communicate effectively we'd have a lot less issue with communication cages.
OP, while making your I statement try to avoid making too big a deal about it. When I got together with my man I had a problem with the fact that he'd call female friends babe. I told him one day, he said it was force of habit and he's try and tone it down. I started calling him baby rather than babe so there'd be some variation. He started calling his female friends baby too! That was about the time I realised that this was rather ingrained in him and wasn't meant as a personal slight to me.
For your GF it may be important to her that the people she loves know it. I have exes that I think of more as friends I was intimate with rather than exes. The way I loved them was so different to how I love my fiance, that even though I have love for them (in one way or another) that love pales in comparison to what I share with my man.
Let her know how you feel but also realise it might not change things.