She’s probably several weeks along. You can wait it out or a vet could perform an x-ray to give you an estimated gestational age of the kittens. Check out our articles on pregnant cats and kittens at the top of the forum. They are very informative and will help you to prepare!
Are you wanting kittens? If not I would just get her spayed asap as if she is pregnant she is very early on. There are lots of lower cost vet clinics, just google low cost vet clinic near me and spay and neuter clinics as well contact rescues to see if they offer rescue rates. Raising a litter of kittens is quite costly so if cost was an issue it would be far cheaper to spay lol.