what do you guys think?

I dont know. About 60% maybe. Just a guess.

In 2017:

In 2018:

Still looking for more recent data.

110%!!!!

Over 60%

I'd imagine that in the first few years, 60% or over would have been the case. As prices drop and switch lite released, more younger fans are getting it under the Christmas tree.

Older fans can afford to buy one at launch, younglings typically can't.

I've seen a lot of women and girls interested in the console, even those who were not into gaming at all.

Physically, or emotionally?

I'd guess 60%

I would say probably 70-75% of the Switch userbase is 16 or older, so basically older teenagers and adults. 

The days of Nintendo's primary audience being 15 years old and younger (read: children) are basically long since done.

Ancedontally too every time I'm in a Switch section at a retail store the average aged person looking at games/accessories in there I'd say would be 16-25 years old, that age group really gravitates to the product it seems.