If your kids ain't neutered you better be home schooling them cause if I catch them in school tryna fuck my kids they're not gonna live to see the pound.
You can't get them fixed before a certain age and that cat might have threaded the needle.
A friend of mine adopted a stray that turned out to be pregnant.
Neutered cats statistically live longer and healthier lives. Fertile animals have health risks. Unless you actually intent to breed your cats, there is no reason to leave them unfixed.
If you can't afford it, don't get a cat. It's like adopting a pet without first figuring out whether you can even buy the food to keep it alive.
My sister found her, my family was not so sure but my sister argued with the idea: the cat stay with us until we find someone else to adopt. The cat won everyone heart in the end, when we got her to the vet to take some medicines we found out that she was pregnant.