They have to make decisions which will have influence on their (mozesz dodac 'whole') lives. 'Controversial question is opinion' (nie za bardzo-popraw) that adolescence is the unhappiest time in most people’s lives.
There are 'a' (niepotr) several 'defects' (calkowicie zle slowo) of adolescence.
They want to have more freedom for example young people love to come back (ale gdzie?) late, but (brak slowa) parents 'parents' (niepotr) don’t allow them because they are afraid 'of them' (nie, tutaj FOR them) or parents 'require too much' (ale czego?) . 'Maturation' (nie za bardzo trafne slowo) is also the time of first love.
They smoke cigarettes and drink alcohol because they want to break away from their problems in school or in (brak przedimka) 'house' (nie, tutaj slowo 'home').
However there are many advantages of BEING AN 'adolescence' (zmien) . 'Youth' THE YOUNG discoveR the world and make new friends.
They usually have a carefree life because they don’t have to worry about their livelihood and their parents just want 'to' (niepotr) their children TO BE well educateD. Another positive aspect of adolescence is joinING voluntary organizations and charities. Young people can develop their hobby and do different things like play 'the' (niepotr) instruments. many people train different sports.
I think the 'most' (daj slowo 'greatest') 'disanvatages' (ortog) of adolescence is that young people have to plan their life when they still do not know (anything?) about it.