Calling teenagers kids in situations like this, or in general is not ideal. The better way is to refer them to minors as this is what they legally are, but even so ‘teenagers’ is how they should be referred to.

It’s probably a lot better to let kids (teens) explore nudity and sex in a safe environment, instead of letting them go unsupervised in places that ignore the law.

Absolutely. It’s only natural for teens/adolescents to be interested in that kind of stuff - they are transitioning into adulthood ffs.