Coming Out Support Group
This community is dedicated to the challenges that gay men and lesbian women face, both between the partners in a relationship and from other influences (family, society, etc.). Find support and talk to others who may be facing the same challenges, and share your experience.
The right time is when you are alone with them. Either it happens or you make it happen. Make sure the enviroment is fairly serious. And when you tell them, try not to sound like you're joking or kidding. Because that will not render the situation to be what you want. But timing is crucial. Wait for general stress level to lower and then pounce. Or poke. For some people, intuition is a well developed sixth sense that they use. You can use this for timing to spring your news.
I kind of went "divide and conquer" with my parents in rapid fire, so you can do that. I think that that went well, honestly.
Chances are, you were in a state of passive denial if there is such a thing before this. You know, when you realize that something's not normal, but you subconciously reject it. That could be a legitamite reply to your mum because lots of people go throught that, and not just about being gay.