how do i know

is there anyway i can if my dog is already spayed without goin to a vet? we got her from a lady who only had her a month, the dog is very well behaved, sits, stays, lays, comes, very tolarent of my children, crate trained, house trained ect. but dont know anything about her medical history. we dont know if she has ever had shots, or spayed, or anything and its quite expensive here to bring in for check ups. i do plan on bringing her in but right now the cash just isnt available, should i be conserned?

[Dan Sims, DVM]

A veterinarian will look for a spay scar which is usually behind her umbilicus or bellybutton. Most towns have low cost vets for vaccines.
She should be vaccinated and examined at one of these clinics.