Jimin’s heart doesn’t stutter this time, but it beats loudly in her ears and rattles all her bones. This is a chance for change and Jimin debates in her loud mind whether or not she should act on her feelings.

With Minjeong standing across from her, glowing like a shooting star—

Her mind quiets down

In other words,

Minjeong is Aeri's little sister and Jimin is Aeri's best friend.