Babysitting

I’m considering babysitting a child (parents are friends of ours) one day a week when their mother returns back to work. The child is the same age as mine (just under 1). My little one isn’t very social and lacks confidence with other kids. I think it would be good for her to have someone to play with even once a week to break out of her shell. For those of you who have committed to sitting for a child, what are the pros and cons? Did it work for you? Is it a big commitment? It would only be one day a week. Is it too much to put on my plate?