I need advice for tonight 10pts?

Well you're obviously not lacking in confidence, so that's a good thing. I would speak to her at the party, but be sure she's not the first person you speak to. glance at her at a distance n give her a lil 'sup" nod, and approach her later. that way she knows you know she's there, but you're not rushin to get to her. When you chat, don't bring too much up from your past. ask her how she is, tell her a little about the good parts of your last 6 yrs, and keep it casual. Tell her it was nice seeing her again and get back to the party. If you end up seeing her again, keep it casual and upbeat. Don't let her go on and on about the past and what a great friend you were and how she regrets things she did bla bla bla. be cordial and nice, but keep your distance.