Hello @Louis14,
You must be 18 or older to have an account on Airbnb.
Also, third party bookings, where the person making the reservation doesn't check in and stay with you, are not allowed.
Section 2.1 of the terms of service mentions the age requirement.
https://www.airbnb.ie/terms
2.1 You must be at least 18 years old and able to enter into legally binding contracts to access and use the Airbnb Platform or register an Airbnb Account. By accessing or using the Airbnb Platform you represent and warrant that you are 18 or older and have the legal capacity and authority to enter into a contract.
The article below address the question of third party bookings.
https://www.airbnb.ie/help/article/427
Steve.