Nanny showing up incredibly early for work

3 times now, our nanny has arrived 45 minutes early, notably on days when there is bad weather. She has told us that she likes to make sure she isn't late, so she would rather risk being early (we do appreciate her wanting to be on time).

The thing is, she only lives 10-15 minutes from our house on a normal day, so we aren't sure why she would ever leave her house an hour before needing to be there. When she arrives, she just comes in. Normally, this is how we do it rather than her knocking or ringing because we're in the middle of our morning routine, and it's easier than having to let her in. But, on these days that she has arrived early (between 6:30 and 7:00), she has just come in with no notice and appeared in our kitchen while we are still groggily prepping for the day and still in pajamas (thankfully we were dressed, at least). We told her previously that we don't mind her coming a little early, but 45 minutes is excessive.

How would you handle this? Tell her to wait in her car? Have her inside and wait (which doesn't really work because the kids know she's there and want to start interacting)? Also, do I have to pay her for the time she's there when she's that early?