You are six when you come to the conclusion that this world is indistinguishable from your last life. There are a few differences in your life, this time you're Japanese, for one. For another, you are an only child (it is very lonely). Your family (and house) is quieter this time around. The world itself though seems unchanged. Oddly enough you are born years before the original you was, perhaps you'll meet your original self with time.
Regardless, you have spent six years attempting to ferret out any clues that this world is different, and it isn't. Although you'll admit to being unsure (you are sure of nothing). After all, you have done your best to maintain a childish persona, which was easier in your younger years when nature forced you to cry and scream. You had instincts when you were younger, which have now started to fade.
Your parents have noticed, perhaps, that you are overly quiet, that your wide eyes and commentary does not have the same number of exclamations as your peers. They are busy however, your father with work and your mother with her puttering about the house making beautiful lunches. She works part-time, mostly because she enjoys it, and you spend that time with your rather strict maternal grandparents. (Your paternal ones are both dead. You don't miss them, you never met them, but you visit their graves with father every year.)
You've started school now, and you are slightly worried your brain will melt. Luckily, your coordination is in need of help, so you aren't completely bored (learning to write is interesting, you're learning to do it in Japanese for the first time). You are also enjoying learning new stretches, you hope to be more limber than in your last lifetime, and your father is encouraging of it.
You are 11 and have given up all hope that this world differs at all from your earlier one. Everything is the same. Same. Same! And you are bored. You are so bored. You didn't realise how agonising it was. You tried, once or twice to get involved, and it was so easy, it really was. You just repeated what the teacher had just said to you, and all the sudden you're the star pupil. (It's harder here, to be the star pupil. Unlike in your schools in your previous life, people care here. For some reason.)
Even answering questions is dull though. In your first life, you enjoyed checking your answer against the teachers, proving your worth, to yourself if no one else. In this one, you know the content as well as they do, if not better.
After a couple of days, you stop raising your hand again and lay your head on your desk (you stop this habit eventually, you don't want to spend forever in detention). You get good grades on your tests, you still can't stand to fail really, you know it's a weakness of yours. Your homework is sloppy, even for a child in elementary school, and on occasion you have to write it during homeroom or in the morning. (You missed a homework, once.)
You are careful though, not too good, not too bad. However happy it would make your parents, you don't want to go through too much testing. You still find it stressful even though you know the content. Even the little tests like how to spell basic words makes your heart palpate (even that is boring though, something you've been dealing with for 30 years now). Now though you don't wonder (quite so often) if you'll fail, not what if you do too well.
Your parents always want you to do better, always. You try a balancing act, as best as you can. You're second, third, or fourth in your class. Never high enough to be top (it's better to be a little under than a little over) but always close enough that your parents are… if not satisfied then at least unwilling to push too much harder. (After all, whenever they look into your room you have your books in front of you, and you do go to piano practice every week, and practice every evening - against your will - despite your lack of improvement.)
However bored you are though, there is a creepy terror in the back of your mind at how empty you are starting to feel. You dislike boredom above everything except perhaps tests. It's a loss either way. If you were a D&D character your alignment would probably be chaotic neutral. Maybe neutral good on a pleasant day. The restrained nature you've been taught in this life is stifling, and although you loath to break it, you're unsure if you can survive another 8 years before returning to the country that has always felt like home.
You realise one day, that you are pretty, according to your standards during your last life. Your parents refuse to let you cut your hair, and your continued stretching and (reluctant) exercise has made sure you are more fit than in your past life. (You reap the benefits of the strict routine your parents have force upon you, it is one of the few parts of their parenting that helps you thrive. Every morning you run the streets of Tokyo, and enjoy seeing the city you so badly wanted to visit in your past life. It's lost most of its thrill now, but you still find it bizarre how you really live here.)
You are 17 when a criminal has a heart attack. You don't realise what's happening at first - of course you don't, why would you. Then a man who goes by Lind L. Tailor comes on TV and renounces someone called Kira. Then he has a heart attack.
You watch it all go by until the television returns to normal as your brain stutters and restarts. You tend to think yourself quite good at coping with new situations, but life as you know it has changed. You have thought you lived in your own world for 10 years now, been almost entirely sure (you're never sure of anything) for six.
You crumble a little, inside, when it occurs that your hope of meeting with your past self, even discretely, even momentarily, is gone.
You realise. You aren't bored anymore.