I'd do her in a second.
As long as she knows a thing or two and you aren't leading her on or coercing her, I would absolutely bang her. Let her take the lead if you're uncomfortable and when things start to heat up and you kiss her, pause, look deeply into her eyes and say, "I must be completely honest with you, I love to fuck two women in the ass at the same time, it's just my thing."
If she smiles and says, "great!" then you know you've found your match!
And seriously, screwing the maid is no biggie. Go for it.