Nobody knows the answer
Nobody can give you an answer to that question.
Something between 1-18 months.
I-140s are very unstable at VSC. Only 12 months ago, you could expect a decision in 6 months.
In the last 6 months, there has been very little progress in their processing (in the 6+ months since I filed my NIW, they have moved 6 weeks).
It is impossible to know whether (1) current processing times will be preserved; (2) processing times will continue to extend; or (3) they will reallocate resources, and the increases in processing times will be partly reversed.
This changes from month to month, so you can't anticipate where things will be a year from now.
Also, times are somewhat different for different categories.
I suggest you prepare for something in the vicinity of 15 months. I very strongly recommend that you protect yourself with a non-immigrant visa (probably an H-1) for at least that long.
Good luck.
Check here often. It's depressing, but habit forming....
