I mean, even if it's raining, why did you invite a girl to your house were you DON'T LIVE ALONE in your first "date"?
She said yes but, at least be sure that you are completely alone in da house before inviting her, like, sending a text or calling to your sisters. My guy will be virgin in his forties if he still being an idiot with those details.
His sisters are not to blame, it's his fault.