See, as a child you have lived in the present. A child cries and the tears are still on its cheeks and it starts smiling again. But if you're upset, for you to smile again may take many months, and sometimes years. This is why I say, "Live in the present moment". It means let go of the past, wake up now, and live every moment.
In this moment there is a depth of the past, and there is a depth of the future as well. But all that is there is only this moment; right now. The past is there only as a memory, the future is there only as a plan, but what is always with us - is the present moment.