They confirm 4 weeks before actual build date I think.
Correct, thought that doesn't tell us much.
To elaborate on AAddict's point, we don't know how long between ordering and building, but 4 weeks before building they "confirm" and some time before that they can "estimate" which is what most of us have now. They do say the outside estimate is 16 weeks. So when you order it should not be more than 12 weeks before you get the confirmed build week (in most cases).
Also, just because someone gets a confirmed built that is a long time away doesn't mean much. Could be that the dealer already used much of their allocation, or perhaps you ordered something like DSG which has restricted supply. I wouldn't read anything into a single case, we'd need a pattern to make such conclusions.