In some countries young people are encouraged to work or travel for a year between finishing high school and starting university studies
.... this is almost one to one from your prompt and that might work against you. Try to tell the same idea, but with different words.
The advocates of this theory arguably have some convincing logical reasons that support the fact that students should utilize the time between finishing the high school and starting university studies efficiently.
... good sentence...it's lengthy, but nicely presented :)
Well... I guess you are preparing for TOEFL or IELTS. If that is the case, you need to manage time for this task very efficiently. So, I'd advice you to follow the four para structure with introduction, 2 body paras and conclusion (you seem to have these features in this essay). However, in your body paras you should restrict yourself giving just one reason to support your argument and then back it up with a specific reason. That's the best way to handle limited time you have for this task.
You write very well !
Good Luck!