She could become pregnant, because sperm is present even in precum, though in small amounts. No one can tell you if she will or not, because you never know for sure. If you are that concerned about it, she may still be able to get the morning-after pill, though she will need to visit her doctor ASAP. I do not know your viewpoints on such a thing, it is only an option. The other is to wait and see. But like IWM said, stress can make one's period late as well, so just keep that in mind.

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I see your fantasy... you want to make it a reality

Are you in the mood to be subdued

You see these shackles
Baby I’m your slave
I’ll let you whip me if I misbehave

Tie me to the bedpost

I like it rough
cause I'd rather feel pain than nothing at all