A few things explained...
So, some people were asking in the comments what the random, plastic letters Marinette was receiving in her envelope were meant to spell. We know that she wasn't able to uncover all the letters because Marinette discovered ahead of time who was sending her secret envelopes and pretty much skipped to the end to confront Adrien about everything.
When Marinette was to receive all the letters, it was meant to spell I'm sorry (which some of you did guess, so congrats!) It was meant to be Adrien's way of trying to apologize to her, until it was, however, ruined and she confronted him head on instead.
Some people were also asking what had happened to Tikki after her fight with Marinette's. The story, as you can see, doesn't specify what happens between them once Adrien and Marinette kiss up on the Eiffel Tower and make peace. The story skips from there to two years later, so of course y'all can assume Marinette and her kwami have made up by then :D
Also, despite ages being posted in the introduction, some people were confused about how old Marinette and Adrien are in this book before their pregnancy. During the time when we only had one season of miraculous ladybug (when this book was written), Adrien was estimated to have turned 16 in the bubbler episode, and Marinette's age was estimated as 15. We now know obviously that was false, considering Marinette was confirmed to be 14 in the Befana episode, and Adrien was confirmed by Gabriel to be 14 as well in the Gorizilla episode.
When I wrote this book, I decided to make Marinette 15 and Adrien 16. At a time lapse of two years, that would put Marinette at 17 and Adrien at 18, which are both consenting ages and even more so in Paris, France, which is where the setting of this story takes place.
In France, the consenting age is technically 15. If 16 year-old Adrien and 15 year-old Marinette were to have sex, it still wouldn't be considered illegal. Of course, I wouldn't necessarily write about kids that young having sex even if it's consensual, but then again, that's just my preference.
That's why I aged them up, even despite still being teenagers. Where I'm from, a 17 and an 18 year old having consensual sex together isn't illegal, nor is it considered rape.
Some people weren't too happy with the fact that Adrien and Marinette were teenage parents in this book, and honestly, I'm sorry that you feel that way. I personally don't see a problem with it. The reality is: there are a lot of teenage parents in this world, some who are responsible and some who are not. I know people who are teenage parents. Some of my friends were teenage parents. I know a lot of people also think it's wrong to have children before you're married, and that was another complaint in this book, but the reality is, a lot of people do it before marriage and have happy lives. What other people do with their lives isn't your concern. Obviously everyone has a different opinion, but it's important to respect everyone's opinion. I think that as long to people love each other, it shouldn't matter. But that's just me.
Also, just because I choose to write about teenage pregnancy does not mean I'm encouraging all teenagers to do the same, but I'm also not doing to dictate what someone does (or wants to do) with their life. That's not my place.
Some people also thought I was making Adrien and Marinette have sex at 14, which is not something I would ever write about or support. So, sorry about all that confusion. I would not write about young kids having sex.
I hope I cleared up pretty much all the confusion people were having upon reading this book. If you have any other questions, please let me know!