Hi , scientific studies have shown that a person's brain doesn't finish developing till he/she is 25, so it's quite possible that a 20 year old will act impulsively & childishly. Women mature faster than men, so that's why they don't usually behave as childishly.

That's normal, I think. Nowadays we live in a society with a high pace, some of us will feel exhausted after one day's work or study. So they wanna find some ways to release their pressure, maybe they behave childishly is just the way they use to relax.

hmm ,Children ,20 years' old ,maybe can't be children ,should be young ,haha

childhood life is the happiest time in our life so that we must treasure it. with the growth of the age, in my opinion, 20-year-old person is not fully belong to the child's age. at that age some time we must bear some resposbility instead of only having our happy time.we must think of our future,our life...... but , its also good, it lead us grow up.i think only can we enjoy our lives, every time seems so beautiful

The childhood are sweet memory; childish will let more people to like you. Over childish will became demanding. ^____^