How far into dating someone w a child do you tell your parents, if at all?

I'm 20 years old and have been officially dating my girlfriend for two months, after talking for three months prior. She has a one year old from a previous relationship, with the father not really being involved he comes and goes. In the past, I've never mentioned any of the girls I've talk to in the past to my parents, but this time it feels different. This relationship being my first real one that I want to be open with my parents about it, including the fact that she has a child. It's something I've been thinking about, deciding when the right time might be to share this with them.