I hope you'll keep her in from now on. The kittens could get hurt outside-predators, rain, chill, dogs, tom cats, etc. I would not let her out, no matter how much she coaxed. Until she's spayed, you'll probably want to keep her in anyway. Cats can get pregnant while nursing their kittens, within a few weeks, and one source said, within four days! Four days really surprised me, but it was a dependable source.
Are you in Birmingham, England or Alabama? My parents were British; that's why I'm asking.