The Nintendo Switch's intended audience is 15 to 30 years old. Every market report I've read says they've been highly successful in their intended market.
The Nintendo Switch has been outselling the PS4 and XboxOne for about a year now. Since it came out much later than either of those consoles, total figures still has PS4 well ahead as the PS4 monthly sales have only been slightly lower than the Switch, but it has outsold the XboxOne in total sales as of about the beginning of this year.