Before three years vs three years before

My grandfather died in 1998. I was born three years before.

Could it be rewritten as- '....I was born before three years'?

The question strikes me because 'before three years' is a common usage-

It's 2017. My brother was born before 5 years= 5 years ago.

I guess, both work here well it's the same with 'after'- Three will be an eclipse after 5 days= 5 days later.

Please help me with the question &:let me know if my assumptions are correct.