Merry Christmas to you all !
She's the right age to be in heat, often the first kitten call is loud meowing with tarty behaviours following.
She should have at least 2 litter trays, you may also need to try different types of litter. Keep her in a small-ish room so she's got no choice but to use the litter.
Beds are common places for young kittens to pee on, make sure you properly clean it with enzyme based washing powder and also clean any other area's she's peed on.
Where abouts do you live? Most countries have low-cost programs, desexing is a very important part of pet ownership and should be factored in when getting a pet.
The more heat cycles she goes through the greater risk to her health and an increased risk to certain cancers. That's why it's best to desex them before their first heat, vets will do it from around 8 weeks/1kg in weight.
I thought so . If you google low cost desexing for your state you should find something. Do make sure she's booked in very soon. I'd be keeping her out the bedroom rather than washing the doona all the time. btw use Biozet or Drive washing powder, they've got the enzymes needed to fully remove all pee odours that kitty will smell.