
Tiffany:
I will rewatch some of episode 1 because I didn't write their age the first time that I have watched it 2 weeks ago.
Yes, that's good! With these reality shows, I find it so important to really pay attention in the first episode or two and to make lots of notes for myself so that I know the contestants. Then in later episodes I can easily speed-watch (at 2X) through the less interesting parts.

Tiffany:
japanese and Mandarin must be really hard specially for reading and writing.
Yes, both languages are very difficult (both the writing and the spoken language), but in very different ways. That being said, Japanese kanji come from Chinese hanzi, so that helps quite a bit (although there are also a lot of faux amis). By comparison, the modern Korean writing system (hangul) is super easy.
I'm not learning to write by hand. That's way too difficult - and my handwriting is already bad enough in English or German, haha.
Languages are a hobby of mine, so I enjoy the challenge.