Hello Mardigras,
Please don't worry about it, the driving looks worse than it is, I have driven for over 20 years in the UK without incident and was terrified about driving here.
Flossie is absolutely right about friday mornings - the roads are full of practising ex-pats just keep your wits about you, drive defensively and expect everyone else to be a terrible driver and act accordingly. Don't worry about the honking either, just don't get involved.
Best advice, feel the fear and do it anyway.
Good Luck.