Can Precum Cause Pregnancy?

Ok so I had sex with my gf and she's crazy scared that's she's gonna get pregnant from Precum. But I know that I didn't Precum and we wore a condom but prior to that I accidentally put it on backwardS before we started but even then I barely put it on and she still washed it off under water with soap. Plus I masterbated 3 times yesterday. Are we ok ?