.....two-year-ago self.........

You are in third grade now. If you could go back in time to the day when you first went to primary school, what would you say to your two-year-ago self?

1. two-year-ago self
2. two years ago self
3. two-year-younger self
4. two years younger self

When I asked my son this question, I stammered at the 'two-year-ago' part. How do you think about the four options above?

Thank you very much. :)

Question

.....two-year-ago self.........

You are in third grade now. If you could go back in time to the day when you first went to primary school, what would you say to your two-year-ago self?

1. two-year-ago self
2. two years ago self
3. two-year-younger self
4. two years younger self

When I asked my son this question, I stammered at the 'two-year-ago' part. How do you think about the four options above?

Thank you very much. :)

Answer

I would suggest:

If you could go back in time to two years ago, what would you say to your younger self?

Answer

The other answers are good.
Other common ways to express similar ideas:

What advice would you give to someone starting primary school?

What do you wish you had known when you started primary school?

What do you wish you had known when starting primary school two years ago?