I really just want to hear feedbacks from people with experience. So I'll know what to expect
I'm studying Japanese at a language school right now.
Do this:
- Study to JLPT N5 in your own country (takes about 75 hours of study)
- Come to Japan and realize you don't know jack
- Attend a decent language school
Expect this:
You will initially love Japan because it will seem like Disney Land, foreign, exotic, etc. After you realize you are essentially equipped with the communication skills of a two-year-old, you will get frustrated. You will be very tempted to give up.
If you continue anyway, after 3~5 months, you will:
- Know enough Japanese to convert your driver's license, open a bank account, get a mobile phone
- Know how to use an ATM in Japanese
- Be able to operate the kiosks in convenience stores
- Go to a Japanese-only-speaking 美容院, order your haircut, and have small talk while you get it
- Gain a vague understanding of what happened when trains break down due to suicide
- Speak to people, make simple requests for things, ask for things, etc. Emphasis on simple
- Not be able to read a newspaper, watch TV, or read manga without help
- Not be able to respond to a random question that a random Japanese stranger asks you quickly
A lot of it has to do with how much you ghettoize yourself. Be sure to avoid foreigner parties and mixer parties and all that crap. Also make sure to avoid Japanese "friends" who only want to speak English with you, or who suggest that "knowing hiragana is enough". They are not your friends.
Your mileage may vary. Hope that helps.