You had best have a sit down with her and explain what you want out of your future. Let her know that you don't think you want the same things and don't want to waste any more of her time. It might be painful for her at first, but ultimately it's the only fair thing to do for her. She probably won't thank you for it, but it's honest and better than letting her believe (erroneously) that you two have a future together. The longer you take the worse it'll be.
Make pony-tail, take one part of the secured rubberband, twist and bend the pony-tail so that it's halfed (bun-loop on one side and end of pony-tail free on the other side), secure rubberband at this half point, twist so that it lays sideways, bun on one side and ends of hair fanned out on the other. Less girly, more samurai-esque. I've seen a lot of waiters/bartenders do this. In your pic you seem to have accomplished something similar anyway, though. Whatever you do, a bit messy works better for guys.
2nd date at your place sounds kind of quick. From an outside POV it looks like you're angling for sex (which you might be). If it was me I'd think it too quick/a bit presumptuous on your part. Unless she seems really into you/has given signs that she's also angling for that, I'd avoid the 'house date' for your 2nd meeting. You could always invite her in after going out if it seemed she was interested.