Spay before she gets pregnant again

Actually we are not cat lovers but for faith she comes to our life so we kind of adopting her. Our cat delivered twice within few months ago which make us headache. It's so hard to see her just born kittens being bite and kill by other big cats. So we have decided to bring her to spay. She's so well behave in the vet clinic, let the vet examined her without making any sounds.  No doubt she's cute little creature!