[Grammar] Before coming here to study, I worked as an engineer for three years. (Correct?)

[priestmoon]

Before coming here to study, I worked as an engineer for three years. (Correct?)
Before coming here to study, I had worked as an engineer for three years. (Correct?)
Before coming here to study, I had been working as an engineer for three years. (Correct?)

(By the way, I'm not an engineer now.)

 

[telemehdi]

"Not a teacher"

first and third one seem correct to me.

 

[5jj]

All three are possible.

 

[MikeNewYork]

Before coming here to study, I worked as an engineer for three years. (Correct?)
Before coming here to study, I had worked as an engineer for three years. (Correct?)
Before coming here to study, I had been working as an engineer for three years. (Correct?)

(By the way, I'm not an engineer now.)

I agree with 5jj. All three are correct.