First of all, the fastest autos will go into pre-flower is at about week 3 - that's the FASTEST... so I wouldn't worry on that score... I've got an auto going now that didn't go into flower until week 7 - different strains, different conditions, different care... but mostly genetics will affect this.
The one thing I DO see that may have set her back a bit is that you transplanted her. Autoflowers need to be started in the pot they're going to finish in as they really don't like to be transplanted and can be severely stunted by that procedure if you damage the roots at all. I would just treat her very kindly from here on out and hope she will recover and give you flowers - but don't start to worry until she gets to about week 7 with no sign of flowers... if that happens, you may as well pitch her.
I would raise your pH a little bit, too... 6.2 is the "sweet spot" ... 6.0 isn't bad (anything lower won't be good at all) but it's amazing how just a few points will improve the grow....
Good luck....
