Rainy, just be polite to her like you would someone you need to feel "formal" around - the bank manager, the headmaster, the queen, etc. LOL And make whatever excuses you need to when you need to step out for a moment - nap, feeds, etc - plenty of excuses when there's a baby on board! You will be fine. If you don't expect her to be on her best behaviour it won't matter so much when she's not, kwim?