And get a deposit big enough to cover notice period, which will be applied to fees at the end of the contract, just in case she quits without notice and leaves you stuck. Plus get paid in advance. If she shows up when fees are due without them, turn her away at the door until she has your money in hand.

I can just see that she might "forget her wallet" so you don't want to be paid after providing care and you don't want her dropping off without payment when fees are due.