Pragmatically, in a home share (versus renting a whole apartment) you have more flexibility.
Hopefully, the government (or even Airbnb) is not going to make you share your home with a crying infant. It just doesn't make sense. Your home space is an intimate space. You can discriminate against sex also.
However, if your space is a 100% private space, you do need to follow Federal guidelines.
You may not discriminate based on family status. If one parent wants to bring his child and you allow two guests, you must accept him.
The only legal way to prevent minors is to limit your offering to one guest only, only adults may make a reservation.