The early demographic for the Switch was heavily skewed, with males accounting for 70% of the of the player base. Over time this has shifted over to an almost 50/50 split between males and females, much more in line with what you would expect from console player bases from the PS4 and Xbox One. In fact, the Switch skews slightly more towards females than either of the other two consoles, which have averaged a 55% male split. Ages for initial Switch owners skewed towards people in their mid-twenties to mid-thirties. Later, demographics would begin to skew both younger and older, suggesting that families and younger people (with little disposable income) were not as quick to adopt the platform right away.
Worth noting, this 50/50 split has been achieved before Animal Crossing has even launched, so that female ratio should get even higher by year's end.
There's a lot more in the article including money spent on gaming and the top five games played by Nintendo Switch owners, well worth a read.
https://www.eedar.com/eedar-blog/2018-q4-round-up