To when would you go back, in time, under the following conditions?

You can go back to any date in your life on Earth so far.
Be it to last week, an hour ago, beginning of last year, or to when you were 12 years old.
You won’t be able to change a thing, you will experience everything that you have experienced already (the first time), and, most important, in the decision to choose the date; you’ll have to life through all the time until you are back to today.
So, if I decide to go back forty years, to when I was twelve, I’ll have to life all forty years again, including all hardships and happy events.