The sweet, smiling, healthy 8 month old boy who is half-suckling, half-sleeping at my boob right now was born at 34w1d due to my pre-e. it's nice you have a few days to prepare. Get Dr Sears' Premature Baby Book. We got that a few weeks in and I wish I had it Day 1. The Fourth Trimester was great, too.
I won't sugarcoat it...magnesium during delivery was hell. Baby in NICU for 10 days=terrifying, harrowing, exhausting, sad. (Didn't feel joy for a long time; I just felt so sad for the poor little guy.)
Now, he's fine. Delightful, easy, happy, healthy, beautiful.
The best advice I got was to remember that your little girl is essentially still a fetus, so focus on testing and keeping her environment as stress-free and womb-like as possible. Cuddle, sing, smile, but don't stimulate too much--preemies are v easily overstimulated. They don't need to be stroked, rocked, and talked to simultaneously, as a 3 month old might enjoy. Don't worry about creating bad habits or doing tummy time or anything. Just take it easy, relax, and keep it easy for her.
Best wishes!!!