Airi has always dreamed of marrying her fated true love and living a normal, happy life – a dream disrupted forever when Aram, a prince from another world, emerges from her grandmother’s mirror. She takes the young prince home with her thinking he is a lost child, giving him a home cooked meal and a place to sleep. However, in the morning she discovers that, as the result of a magic spell, Aram transforms into a 17-year-old boy whenever it’s dark, and her kiss is the only way to change him back! If that wasn’t enough, Aram is in hiding from his older brother, the evil sorcerer Jeile, who has fallen in love with Airi and intends to make her his bride! Will Airi ever be able to find her happily-ever-after?
Please Save My Earth like Merupuri has a highschool girl paired up with a much younger, yet mature boy. But it also has a much better story, lots of drama and it's fairly long. If you liked Meurpuri, you might like Please Save My Earth too.
Once there lived an eccentric author called Drosselmeyer who wrote grand tragedies - one of them was the tale of a prince who sealed away an evil raven by breaking his own heart into tiny pieces. However, before the story could be completed, the author died and the tale took on a life of its own. Now, in a town where fiction and reality meet, the story continues on its tragic course with Ahiru, a duck who transforms into the beautiful Princess Tutu in order to restore the prince's heart. But will Ahiru's act of love be enough to defy the story's terrible destiny and lead to a happy ending?
Age transformations via kissing; Thats the only thing Sakuranbo Syndrome and Merupuri have in common, but if you found that theme interesting, you know where to look.
P.S. Just a word of warrning: Sakuranbo Syndrome can get quite mature at times.
Snow White’s stepmother has always hated her for being more beautiful, and is now after her life. Luckily the young princess has managed to escape to a small house in the forest inhabited by seven dwarves who have offered her sanctuary in return for her assistance. Unfortunately, she can’t cook, her idea of cleaning is calling in the help, and her haughty attitude doesn’t sit well with one of the dwarves, Seven. However, as Snow White begins to try her hardest it seems that maybe Seven doesn’t hate her after all…
In both manga the female lead is taller than the male lead and in both there is age transformation involved at some point, not to mention both series have this fairytale feel to them. Unfortunately both of those series are generic and mediocre shoujo ones, but if you enjoyed one of them you'll probably like the other one as well.
Both of those shoujo manga feature a kid prince being paired up with an older girl and in all honesty this should be more then enough for you to decide whether to read one of them or not if you already read the other.
P.S. I find Soredemo Sekai wa Utsukushii to be the better one of those two.