Why do you have to be 35+ to run for president?

According to me there is a strict reason behind this, maturity can act on a person with great measures.

Explanation:

In brief I could say that the amount of education one might need to satisfy the needs of running a parliament or a country can only be performed if the maturity level of a person is high, this is usually achieved in the years of 30 above. Education is needed for running a country hence the amount of knowledge one might need to run it can be achieved only after one sees the world. Hope this answer is good enough!