We started weaning at 4 and a half months actual as Abby was a huuuungry girl and I couldn't keep up!
We just gave baby rice at that point, for about a month then moved on to purees (have a look at my facebook video for her first attempt, it was very funny!)
She is still on purees, rice and porridge and she gets these 2-3 times a day.
I was told 6 months actual but I believe bliss says between 5-7 months actual. If I'd waited til 6 months corrected Abby would have been nearly 9 months old. Not sure who told you to go by corrected age, but perhaps they haven't much experience of preemies?
But you'll maybe have noticed by now that some of her development is following corrected and some is following her actual age? At least, that's what we've found with Abby.