So this HB8 and I used to talk before now and we stopped talking and I liked her. Today was Formal Day for Homecoming Week at school so I dressed like a sexy beast in a suit and I walked in this room to help her and these two other guys with a project. Before today, we haven't talked barely for like 3 months and when I walked in she waved really excitedly and said "Wow you dressed up!" Then she insisted we get a picture and her friend took the picture and we had our arms around each other's waists. I commented on it, helped them, and left. I don't have her number anymore because I got a new phone, so now I want to get it by asking for the picture. On Facebook, should I message her when she's offline as if I'm busy and I only had time to send it and leave, or should I wait until I see she is online and ask her there so she can reply? Or should I wait until tomorrow at school if I see her? I prefer Facebook because I don't want my anxiety to ruin this for the second time. What do I do?