Welcome Nocturne!
You sound like you're in a pretty similar situation to my own down to the pressured to get baptised young by my single mom and the "If you were to leave the truth..." speeches. I wish you the best of luck in whatever you decide to do.
I left "the truth" 10 years ago when I graduated high school. For me personally, although my mom took it hard, she did not "die". It was hard at first, but it got easier with time. I would not go back or change my decision for anything! I learned later that the speeches my mom used to give me have a name...emotional blackmail.
Best of luck to you - Smurfette