I’ll answer this because my son was a live-in nanny for three different families. He was American/they were American, so the kids didn’t get the advantage of a second language. But he was an excellent nanny. During college he worked for a professorial family. Their deal was that he worked 15 hours/week (with 3 very young kids) for room and board, and beyond that, they paid him per hour. The classic “con” is that the au pair’s youthful adorableness is so titillating that one of the parents falls for her or him, and all hell breaks loose. The other classic “con” is that s/he’s terrible with children but you aren’t smart enough to give her a trial run. So, do that. A classic “pro” is the fun of having a person in the house who’s between your age and the kids’, and the practice you get in finishing up the raising of a young adult. And, if she’s foreign, the likelihood of having people in another country to visit later. Good luck. Could be great. Will be challenging too.