Depending on women to women. Clomid can start your ovulation depending on length of your cycle. i had 37 day long cycle so i use to ovulate CD24 then i started my cycle 28-30 so i use to ovulate CD14 or CD17. so it does fix days of your cycle thus reducing days of your ovulation. if you had cycle of 30 before clomid it may reduce your cycle length. plus i would say keep testing not only with BBT but also with Ovulation kit. it will help you determine the right time and day.
I also ovulated early. I just finished my first round of Clomid beginning of Nov.3rd. I was suppose to start ovulating cd12 (Nov. 8) but I started on cd9 (Nov.5)...
I've also heard that Clomid can make you ovulate sooner.
Good luck to you!