I wouldn't read into it too much if I were you. Just enjoy the fact that a girl liked you (as a person, not necessarily in a romantic sense) enough to hug you. However, feel free to ask her out on a date, using casual language in the process, something like: "I'll be doing [activity] at [date and time]. Do you want to join me?" In her mind, it creates less pressure (supposedly, she's simply joining you for [activity], rather than going on a date), even though practically, it's still date. While on a date, flirt with her. Examples of that would include briefly touching her to emphasize a point, reading books from the Sexuality section in a bookstore, or simply making her laugh. Good luck.