It’s very likely just the wide range of autoflowers seed to harvest time.. unfortunately it’s all over the place even if they quote a certain time frame.
To illustrate this point I’d recommend just perusing the autoflower diaries on this site that have been harvested and then cross reference their breeders supposed time frame.. ppl have 60-70 days ones that go 100-120 days. Plant looks good tho I wouldn’t stress it. It’s just one of those things they don’t quite advertise - but it’s true. Good luck!