Elle is with her best friend Ace planning what they are gonna do in there senior year
Elles parents tell her when she turns 18 she will gain superhuman powers (strength of 10 men) which she can't tell anyone and will have to leave home for a while until she can fully control it.
Crossing The Threshold
She stumbles upon a man who hit his dog and was yelling at him, she did not help because she knew she'd have to use her strength. She asks Ace what she should do but he doesn't believe her.
Elles grandpa calls to see how she's doing because he was told the same news as her on his 18th birthday. He tells her to at least consider it because when she gets his age she'll either regret her decision or be proud of it.
Her grandpa tells her to go to where some heroes live on Wavy street. She realizes that they are just regular people and it makes her more comfortable with deciding whether or not she wants to accept her powers like they all did
Elle says something about Serena a villain, and her "friend" Amanda who she had only known for a few weeks told her. Serena shows up to Elles school disguised.