@Sami459 Of course you have the right to not accept children.
But since you are a new poster here, and for informational purposes, I would just point out that if you spend some time reading posts on this forum regarding guests causing damages, which are numerous, you will find that they almost never involve children. It is adult guests who cause the vast majority of damages.
A broken window from dad playing snowball fight with his kid? That has nothing to do with the kid- Dad shouldn't have been having a snowball fight anywhere near where would be a possibility to break a window. That's just common sense. He could just as easily have been playing softball catch with an adult buddy and broken a window.
Yes, kids can leave sticky handprints on the walls. Adults can leave drink marks on the wooden furniture. Yes, kids can drip ice cream on your throw pillows. Adults can use your nice towels to wipe off makeup or climb into bed smeared with sunscreen that stains the sheets.
If there are reasons why a property wouldn't be safe for children, then 'not suitable for children' is a good rule to have. Likewise if the house is in a neighborhood largely populated by adults who would be disturbed by kids running around having fun, and making kid noise.
But to not accept children simply because you think you'll avoid damages by doing so isn't an idea borne out by hosts reports here on the forum or any other hosting forum I've read, nor by any other hosts I personally know.