I’m torn on this but I honestly think you’ve suffered from some limiting factors that caused those buds to stay smaller.. but would say you are right about 2-3.5 weeks from the harvest date.
It looks like they’re damn near finished right now by some factors, yet looks also like you’ve got a ton of growth to put on.. which would mean 4 weeks at least.
If you don’t have a 30x-60x jeweler loupe to check trichomes - order one now. To me - This is just one of those plants you absolutely need to see the trichs up close to decide on harvest date.
If you don’t have the means to get one, my best guess is to start flushing in a few days and then chop in 14 from today.
Autos are weird like that and that’s why I don’t like them personally.
Good luck!