You can take her to an exotics vet for a checkup. An experienced vet may be able to palpate the fetuses if she's far enough along, otherwise they'll need to do an x-ray to see.
Alternatively, you can also wait until 75 days from the date that you purchased her, since that's the last possible day of gestation.
We are as gods to the beasts of the fields. We order the time o' their birth and the time o' their death. Between times, we ha' a duty. - Terry Pratchett.
"Men have forgotten this truth", said the fox, "But you must not forget it. You become responsible, forever, for what you have tamed. - Antoine de Saint-Exupéry