I still think what happened in "BlueJay" and events surrounding it are "The Catalyst" (Heh, another "C" word!) for Makoto being able to go to the roof, she even remembers it vividly in chapter 3 after several Resets had past even though Akira doesn't.
I think the bluejay thing plays a factor but it is not enough, if that is the case she should have arrived at the rooftop much earlier so it only gives more weight to the way Ayane arrived with the pregnancy.
but I admit the fact that we do not know how many bluejays there were but some events give clues that there were much more, all that number of bluejays made many short circuits in her memories, possibly I suspect having a better reset memory making comparisons.
((((because possibly many other girls would have committed suicide a lot of times in this infinite sea of resets and nothing else would have ever happened to their memories, so there is also something special with Makoto from the beginning))))
I also sense that something or someone wants her to get to the Rooftop.
Then she had the need for the news of her dead father, which may or may not have been manufactured by the world perhaps implying that if someone wanted her to come and find out about the reset rooftop
and the last part getting to have sex with sensei,
so there are
3 important factors in makoto as such, All the Bluejay, and her daddy issues and how she breaks down knowing that her father has died and her other father figure has not really loved her, he has actually taken advantage of her, so when she solves those two ''conflicts'' and then being the icing on the cake, that Sensei now ''loves'' her or in what his conception of love is, + unprotected sex.
((because the thing is, even if 3000000 bluejays and a lot of sex with Akira have passed, the reality is that possibly if Makoto's father had not died or his news as such, she would not be on the rooftop)) ((It would not have led to the relationship that Makoto has with Akira at this moment. tho))