Which lines in this passage are a flashback?
Helen stood at one end of the room taking in all the activity; Rupert and Phoebe danced to the loud music that drowned all other voices. Food, friends, music—how they brought people together. She thought of her last day in middle school, seven years ago, when Sarah had given her an iPod. She had felt ecstatic that day when she realized she would be able to listen to her favorite songs and fend off comments from her cousins about how little she knew about music.
She smiled as she drew out the envelope from her clutch. Tomorrow at this time she would be performing solo at the Royal Hall of Music; she could almost hear the thunderous applause. The music stopped and Phoebe called out her name. Helen almost dropped the envelope as she walked up to congratulate Phoebe.