My youngest daughter is due to give birth to my first grandchild in 7 weeks. She's quite used to looking after kids, as she helped her mum (my late wife) who was a childminder for 23 years, and has also worked as a nanny for 3 or 4 years. She wants to become a Youth Worker, and sees her time looking after the baby/toddler as a time to get a professional qualification to help her in the future.
She knows that no baby comes with a workshop manual, and what to expect in terms of sleepless nights, sickness, etc. She knows all about naughty steps, how to control tantrums, bad behaviour, etc as defined by OFSTED, as she was registered by them when a nanny.
However, the big difference between your own and ones you are looking after, is that they're your responsibility 24/7, and you can't hand them back at 6:00pm. They're yours for many years.
Fortunately, she's got a dad and sister who will back her all the way (we must be bloody mad!), and, of course, the baby WILL be a blue!