Hi! There is no mistake. You only need to complete all the quests with the girls in the alley.
I already did that. all three require: "Go through Bonny's storyline, then come back when you have access to the club"
Edit: found the problem: every time i opened the portal, it had an authors note saying you'll die so i assumed it just led to a soft game over. tried going through, got killed, then talked to littli and that worked. but really, i feel like having that "warning" there has probably been a problem for other people too, i advise changing that in some way.