@Christina666, like @Robin129 said, most importantly 3rd party bookings are against airbnb policy. If there were an incident at your house, you would not be covered by the host guarantee.
In truth if you don't mind doing a 3rd party booking as a host, airbnb couldn't really care less from what I"ve heard. And if you have your own tenants insurance, you're covered if there is an incident anyway.
But this rule is a great "out" for you. Just tell the guests, you'd LOVE to host, but it's against airbnb policy and you'd hate for them to be unprotected should something go wrong.
also when someone books on behalf of someone else, the someone else is frequently unaware of things stated in the listing and the house rules. Bit of a recipe for disaster really.
so all up, better for them to do it themselves. @Robin129 has given you all the links you need.
Good luck!