Hello!
Thank you for playing and very happy to hear you are having fun with the game. From Chapter 2 you get a new UI screen that shows all the girls and their relationship scores. This is in the current game (v1.2). If you are still in Chapter 1 you don't have it yet.
Relationship score only starts to impact dialogs from Chapter 2. Usually above or below 5 will result in different dialogs.
Ok and the truth is thank you very much for answering, I would also like to know if in the next v1.3 update there are missions with PIXIE the ada And also missions with Rachel Kim's sister and Millie's mom? Since they are two beautiful characters and it would be a shame if those characters are lost and they do not have some spicy missions with the player, where somehow the Milfs or mature can also enter in this extraordinary story.