By 20 you should know this:
- How to cook 10 good meals
- How to dress like an adult and not a teenager
- How to get enough sleep on a daily basis
- How to manage your tasks, projects, and calendars so that you never miss a date or forget anything important.
- How to read 100 pages in a day with the same comprehension you would experience if they were spoken to you.
- How to relate to the opposite sex without objectifying them or being afraid of them.
- How to break arbitrary addictions: soda, Facebook, TV, video games, tobacco
- How to pay bills on time and not spend more than you can afford
- How to be comfortable in your own skin, without constant need of affirmation, showing off, sounding smart, whatever.
Check out this list with more details. It is worth the visit: