Oh cool....I got the wrong Idea....
...
MELONLORD SHALL DEFEAT THE AVATAR!
Yeah, me neither
In a passive way....it'll just change a few lines from the previous main girls you could've encountered in the past. (But
Heavily affect Book 2 in a way if you're going for Book 4's love route) and will make the story so complicated for you in so many ways
But the story and the events of the story aren't affected at all!
Not to mention that progressing relies on doing tasks and what others tell you to do if you're planning on skipping text/dialogue as well
TL;DR
It'll just passively affect how the past girls deal with you in a way without affecting the story's events.
Skipping also makes life in this game hell, complicates the story and make it sound boring (and makes progressing and getting scenes harder!)