I am not expert but I think from what I have read that an early crop is also down to the variety? I have one from Real seeds that Latah, which is bred to crop in a very short season, in this case I believe it is 12 weeks. Obviously you will need to be able to provide warmth and good light levels to achieve this.
Im hoping that they will be fine from a Late Feb sowing and still produce an early crop as my sowing plans for this year are changing by the day.
Bluebell