For that reason, some people advocate that somecertain difficulties people metmeet inat their early ages will become an invaluable fortunelessons in their future lives.
... Keep the sentence in present tense. Also, fortune is associated with wealth, but here it is different.
From my point of view, I am in favor the former statement that some tough experiences people met before will be helpful in their life path.
From my point of view, I am in favor of the former view because I believe the lessons that we learned from the hardships in the past would immensely help us to be successful in future.To start with, hardship makes people realize how to cherish and compliment the common but wonderful little things happened in their life such as, a shining weather, a delicious breakfast and etc. People who have such nice spirit usually know how to find the true love in their life instead of being seduced by greed as to lose themselves in the end. As a result, experiences of difficulties teach them how to keep a nice mood and have confidence all the time.
Your idea does not flow through well here, especially the first line. Avoid writing too long sentences.
First, hardships make people realize and appreciate things. For example, if one had been very poor during his/her childhood, then this person understands the difficulties of being poor. When he/she becomes rich, this person would not waste money but carefully manage his/her wealth.