This topic is a matter of opinion. Someone who is fed up with the "man" would say the purpose of life is to do nothing but grow up, attend college, get a job, pay taxes, etc. Someone who is has been hurt one to many times would say there is no purpose to life. Basically, there is no DIRECT matter to purpose of life, but what YOU make the purpose of your life. Your here to live your life, do it your way. Thrive in a purpose that makes you happy c:
The purpose of life is to reproduce. All organisms need to reproduce in order to replicate and pass on their genes to their next generations. All species do this to keep their kind alive.
Now, that doesn't mean that you are 110% required to reproduce or else you'll get punished. Not everybody has to do it. Like the other answerer mentioned, peoples' viewpoint regarding the purpose of life can vary. Some may agree with me, some may not.
In turn, you can decide for yourself as to what the true purpose of life is. And, again, people may not agree with you. But hey, it's your opinion. Not everyone in the world will 100% agree with others' opinions. So if you think the purpose of life is path A, then so be it. No one else has the right to tell you otherwise.
Unless you become a serial killer or something...