The true purpose of this life, is first and without any doubt to Live .
When this is fully and "Sincerely" understood , note I said "Sincerely" it requires "your truth" Then we can all joyfully go about our own merry way, seeking our own individual purpose.
Starting with the example shown to you by your parents, you will quickly grow and learn to pick sense out of whatever position they are possibly at. You can grow to teach your parents, give a more profound guidance, with your sincere truth.
In some places it is a must, that you follow in your parents footsteps . Even in these places, one will still find his true purpose, life will always show you.
My humble recommendation is for every one, is to try starting with your belief . If you have not found it , you "Must" search for and find it, It usually finds you. We as humans do come with one. What some humans do in life, is to deny this.
Then their life becomes a constant struggle, a confusion.
The true purpose of life is live knowing that there is a purpose and you must not stop until you find it!.