So, My Girlfriend And I Were Having A Fun Night,

So, my girlfriend and I were having a fun night, that then engaged in sexual activity but I did not finish nor go deep enough to have a risk of it (it was her first time so we took things slow) she is now showing symptoms of pregnancy, nausea, missed period, and sharp stomach pains. my only reasonable thought to this is before we started having sex I rubbed precum off with my fingertips and about twenty minutes later I fingered her but went alot further in than before could that fertilize an egg, and cause her to be pregnant?