In three months I've done over 7,000 km in my GT. No issues with oil change light. In earlier research a was advised by an experienced mechanic that oil change more likely to effect cars doing a lot of stop / start (i.e. city) driving. Most of my driving is highway and expressway with little city driving. Are you urban or highway driving predominantly?
Go into settings and reset the oil change button/setting. There have been a few posts on this, it happened to me. I also had to reset the tyre pressure monitor as it said the r/h/f was way too low but when I checked with a hand pressure gauge it was spot on. Reset the tyre pressure monitor and no worries.
I think it works on both k's and time.