Highly disagree, teens around the world tend to have normal sexual encounters before that age. By setting a minimum age you are just telling your kid to hide it from you until that age, which will probably result in less safe sex in less safe spaces. The right way to approach this is to be attentive and communicate with your child so that you are aware of where they are in their life and can talk to them if needed.

If your child is 14 and intends on having sex, you can either show them that they can come to you for help and guidance, or you can show them that they can't, either way they will probably do what they want.

The awkwardness and discomfort of teens having sex in your house is much better than letting them do it behind your back, possibly in an safe way and in an unsafe place.

For reference: https://www.centreforsexuality.ca/learning-centre/stages-of-child-sexual-development/

This is so weird to me, but sure, customs differ.

Around here kids today have penetrative sex from 12-13 years of age, would you rather they do in school bathrooms, back alleys, bushes, or somewhere clean and safe where they can also get help from a trusted adult if something goes wrong?