Artima was good with kids. This was a fact that she knew to be true and insisted on regularly despite not having any regular contact with kids. Sure Ben and Mika counted but she was almost never left alone with them and they were both old enough to feed and take care of themselves so they didn’t really count when it came to the whole babysitting thing. But a new baby? That was an opportunity that she was not going to pass up.
Sure Kara had done everything in her power to keep Artima from being alone with the little thing but eventually Culen and Briika had given in and agreed to let Artima watch their kid on her own. It wasn’t ideal considering she was stuck at Kara’s place on Concord Dawn and once Kara got home from whatever job she was on she was going to help Artima out, but having the little girl to herself for most of the day was pretty much everything Artima had wanted.