If you cannot answer this question when you are 14, then probably you cannot answer it at 24, 34, 44 or 54 until one day you are 104.
The pressure in life will help a bit. You will be too busy working for a living; you have no time to think about it.
Until one day the pressure was gone.
And the question would come back. You will ask yourself when you are 104: What am I living for?
Some people have an early instinct to know such questions. They never have to ask it. They have a feeling knowing what to do. They are interested in something, or many things in life. They have an aim in life. They are lucky ones.
The secret of the instinct is to look outside, not to see inside. The lucky ones are the same human beings. They also have life pressure. But they know what to do in life.
People without instinct must solve the problem when they were young. Or seek help with social workers, teachers, philosophers, etc.
Don't wait until you are 104.
9048 what to do if you are 104 years old? 20170315