Lol. I've had girls initiate texting multiple times a day and flake on the meetup and girls who never text me first but if I hit them up at 11 PM they're on their way (no excuses).
Then, there's when you're relegated to being her phone buddy, which you can find plenty of stories online about, especially LDRs, where you have girls texting guys everyday for years. But she's only interested in the attention.
I've also had girls whose conception of ladyhood involves never texting first--but always answering texts in a timely manner.
As much as guys would love some logical set of 'rules,' in 2017, you can throw that out the window. Every girl is running her own game, play yours accordingly. Stop worrying about her interest level in you & start focusing on your interest level in her.