If you could travel through time and space, where would you like to go back?

If I can travel through time and space, I want to go back and study hard

Now I got a third-rate job. My daily goal is just to take care of myself, and money is often not enough. But being able to eat and wear warm clothes is no longer a luxury. If I can travel through time and space, I want to go back to the past, study hard and work hard, so that I won't grovel at people every day.

So if I can travel back, I want to choose to study hard.