You can see the small arrows in red that show where the 0 voltage is for that specific channel.
As for the time - it does not matter where the 0 is, because the 0 time depends on where the measurement is triggered.
For your case - the 0 time is the rising edge of Vin (see the arrows in green.)
This picture only serves to show that Vout rises ~37mS after Vin.
Zero time in a scope does not start at the beginning of the screen.