Seal the deal with a girl..?

Recently, I have gotten around the brotherly curse. (AKA, being only seen as a brother.) I took her out for a date, and it ended with us kissing and holding hands. I'd say a success. But talking to her today, she didn't seem to chatty. I'm kind of worried. I mean, last night we seemed really close. (There was no alcohol or drugs involved.) Is there something I should do at this point to kind of make sure I have her, or is this one of those "time will tell" kind of deals.