"The guru is in you" does not mean that you don't need any outer guru or teachers. We all need outer knowledge to open ourselves to inner experience. The phrase is intended as a constant reminder that your enlightenment depends on you more than anyone, because it is only through your desire and action that divine experience can rise in you.
Maybe your journey means surrendering at the feet of an outer guru for your whole life. Or maybe it means purifying yourself by following a number of teachers over your lifetime. Whatever the outer relationships turn out to be, it is the divine expression coming from inside through your heart's longing that will lead you to them. What is happening outside is a reflection of what is happening inside, not the other way around.