since ten years old

[JEic]

Are both sentences correct?

(a) Leroy has been learning golf since ten years old. (Although it sounds a little weird not to put "he was", I feel it is clear who the subject is)
(b) Leroy has been learning golf since he was ten.

 

[5jj]

a) No.
b) Yes.

 

[JEic]

a) No.
b) Yes.

I would appreciate it if you could help me to understand why (a) is incorrect.

For example, "I have been living in the West since 2020." (after this "since", I put the "time")

Why is it that (a) cannot do the same thing?

 

[5jj]

Since must be followed by a time-point for example, the age of ten, his tenth birthday.

 

[JEic]

Since must be followed by a time-point for example, the age of ten, his tenth birthday.

Pardon me, isn't "ten years old" also a time-point? "....... since ten years old"

 

[5jj]

No. Since has was ten years old gives us a time-point.

 

[JEic]

No. Since has was ten years old gives us a time-point.

Please pardon me. Is "2020" a time-point as in "I have been living in the West since 2020."

Can "ten-year-old" then be considered a time-point.

Pardon me, I'm trying very hard to understand.

 

[5jj]

Yes.
No.

Ten years old is an age.