under 16 no license needed. Can they take your gear, not fully sure. But fishing fresh water without a license is a fine of $95 but it allows you to fish for the rest of the day.
They offer a 1 day, 7 day and a 1 years fishing license for fresh water
link above very helpful as well as this one:
https://www.wildlife.state.nh.us/fishing/index.html
can even buy at Wallyworld