Q. You're receiving a letter from your future self. What do you think it'll say?
I'm still working as an idol now.
Please relax.
I'm enjoying li~~~fe!!!
I'm very happy now!
Believe in yourself and do your best without giving up, okay ☆
"You should study properly!"
"Hello! Mai~. How are you~? Mai is well~! It's incredibly fun right now!
Life! And so now, be sure to properly enjoy being 13 years old~!"
is what I think would be written.