I highly doubt you would be terminated for this. However, I am sort of confused about what happened? I am guessing you drove by out of curiosity, but:

Did you stop in front of the house and stare at it?
Did you beep the horn? I'm only asking this because I'm wondering how you would think she know you drove by.
Is her house in your area and you could pass it off as just passing through the neighborhood?

Are you planning to discuss this with her or are you just afraid she will bring it up?