I'm 20, female, and I regularly chat with a man here who is 48. Our conversation is definitely non-sexual, yet i count him as one of my friends here. Although friendships with large age differences can exist in real life, they are much easier to maintain over the anonymity of the internet, and I think that people who don't regularly use the internet dont understand the good relationships that can be built up between people. My father does not really understand chat and his greatest concern is that I can't ascertain who i am talking to, and of course people can pretend to be somebody they are not. But still... maybe you should just not mention chat so much to your gf. if she doesnt really understand it, why upset her if you dont have to do? maybe you should just downplay it.