You are not living in the present when you ba<x>se your life on worry about what might happen in the future, or when you cant let go of the things that have happened to you in the past and you allow your present choices to be decided by the pain, fear, or joy that you felt in a past situation. Each day, each new circumstance. needs to be chosen on its own worth, you can only live in today.
When you can time travel into the past.
as soon as you're consciously aware, it is so.
when you can smell farts you neither felt nor dealt
When you sit there thinking about nothing but your past and what you could have done to make the future better.