I was going to reply to another post with this, but I think this works better as its own post. There's been a confusion with the timeline of the series that I want to try and clear up with this post. And that confusion is: “When did Princess Charlotte get the Amulet of Avalor if Tilly had it at some point?”
TLDR; Charlotte must have gotten the amulet after Tilly, Tilly was not the last Princess to use the amulet before Sofia.
In the episode “The Secret Library” there is this exchange:
Sofia: “How did you find this place?”
Tilly: “The same way as you dear, although I did it 30 years ago.”
This is probably an approximate number but using this number as an estimate would place her as being somewhere in her 40s. This also means that the amulet was in her possession approximately 30 years ago, but the amulet has only been in circulation outside of Avalor for the past 41 years.
But in the episode “Beauty is the Beast" Princess Charlotte recognizes the amulet Sofia is wearing and says that she used to have one just like it. Then Sofia comes to the conclusion that it was the same amulet. And that the amulet connects all the princesses whoever wore it so that's why it's summoned her to help. The thing is Princess Charlotte seems a lot younger than Tilly, since she still lives with her parents and acts immature, so it doesn't seem like she could have gotten the amulet before Tilly, but how could she have gotten the amulet after Tilly if it was being kept in the Enchancian royal treasury at the start of the show?
Now many people in the fandom at large assume that Tilly was the last princess to receive and wear the amulet before it was put away in the Enchancian royal treasury until it was given to Sofia. But I don't think that that is the case, and the show has evidence towards that not being the case.
First of all, in “Elena and the Secret of Avalor,” Alacazar says: I searched the globe for years, until I grew too old to continue, and used the last of my magic to transform myself into this book.” And his flashback shows him going from having fully brown hair and a lot of strength to having fully white hair and needing a cane to slowly walk. If he spent his time traveling the world for approximately 11 years before giving the amulet to Tilly and turning into a book, then he was aging remarkably fast.
There is also a little bit of evidence that Alacazar was actually working with Goodwin at some point considering that in the royal sorcerer tower in Enchancia they have a book that talks about the amulet and even about how to possibly release someone from the amulet that has pictures of the amulet being purple. The amulet was red before Elena was put into it, and pink after she got out of it, so that part of the book could only have been made during the 41 years.
So the most likely explanation for the timeline of events is that Alacazar traveled around for about 11 years giving the amulet to different princesses before he gave it to Princess Tilly, she had it for a certain number of years during which she discovered the secret library and became Storykeeper. During this time Alacazar Probably worked with Goodwin to see if there were any alternative ways of letting Elena out of the amulet that were possible. Then Tilly grew too old for the plan Elena had in mind/was judged in some other way to not be suitable to free Elena, so Alacazar took the amulet back and gave it to more princesses. During this time he probably gave it to Princess Charlotte which would explain why she's younger than Tilly but still got the amulet. Then he became too old and weak to continue giving the amulet to princesses and turned himself into a book inside the Secret Library. But beforehand he either must have given the amulet to King Roland ii who put it in the treasury for safekeeping. Or gave it to Tilly to give to another Princess, but she put it in the royal treasury at some point while she was adventuring and so busy with something else that she couldn't even go to her own brother’s wedding.
We know for a fact that Roland had no idea there was a Princess trapped inside of the amulet, and that Elena specifically made the amulet glow in order to get Roland to notice it and give it to Sofia as a gift. That actually would be a very Elena thing to do, if she was supposed to wait for Tilly to get back and give the amulet to another Princess but then just decides: “Hey there's a new Princess here, so I'm going to make sure the amulet goes to her instead.” Very impulsive Elena thing to do, and it ended up working out perfectly, also a very Elena thing to happen. Roland also concludes in the episode “The Amulet of Avalor” that the amulet might have purposefully chosen Sofia to wear it but never questions how a supposedly inanimate object could make decisions like this. Then again Roland has a lot of experience with magical objects that do magical things and he does talk to them like they are people (with both the magic mirror and the well). So who knows, maybe this is normal or maybe he is weird.
So that answers the question of how Charlotte got the amulet after Tilly, Tilly was not the last Princess to use the amulet before Sofia.
Also as a bonus thing I noticed: Roland says that he knew that the amulet would “watch over the Princess who wore it” because his mum told him stories about it. Not his sister, who actually had the amulet, his mum. Grandmum knew about the amulet too, but we have no idea how. Did Tilly tell her? Alacazar? Goodwin? Grandmum is old enough to have met Elena, Queen Lucia and King Raul before Avalor was taken over, did one of them tell her during a royal event or visit? And then however she learned the information she decided that the stories would be fun stories to tell her son. I guess Tilly actually isn't as weird as a lot of people think considering her mom and brother are clearly also weird, they're both just not as openly whimsical as her.
