GIRL TROUBLE! Please Help?

Ok, so here's a story. I met this girl through her sister who was celebrating her bday. Went to the bar we were flirting back and forth all night. We bought each other drinks, and just flirted without dancing or anything majorly ual. Ok so the 5-6 girls and 2-3 guys we're with all left somewhere and suddenly we were kind of alone on the dance floor, so i figure great time to close. I continued to flirt get her dancing with me flirting.. back and forth etc, then finally im straight up and find out her sisters friend wants to bang me. She didn't want to do that to her sisters friend who she knows also, so she says she won't hook up with me, plus she had a guy coming to pick her up to hang out with her that night. People come back, she says bye and leaves. I for some weird reason.. run after her down the street, meet up with her and continue to talk more, but don`t press or force anything. This girl is 28, a high school teacher and incredibly HOT, I think i`m in over my head. He comes, she walks off with him, the whole look back and a little wave thing, lame. Anyways, we`ve been texting a tiny bit, nothing major i can`t read her, but she says she will go out to dinner with me. So i`m trying to plan this out, i`m 20, i don`t date, Idk what the eff`s going on. But I plan to take her to a nice... kind of private place downtown, near water, give her a rose and just talk to her first about things, semi-seriously. And then.. take her to a nice resturant blah blah. Suggestions...anyone of you experienced ones.