My 33 Weeker, was in the NICU for a total of 26 days, she was 3pds 3ounces. The first week was for jandice and keeping her temp up, then next two weeks was trying to get her to eat, she was ready just lazy. Once I conviced the Dr's to take out her feeding tube (they did not want to B/C of her weight) she came home two days later eating fine. I think for the most part a baby without many complications can come home closer to the 36 week gestation, but if they have more issues then they are more likely to go home closer to term. And of course you will hear from the doctors that every baby is different.
Mine came home at 36 1/2 weeks gestation 4pds on the nose. And yes Girls tend to due way better as premies, so that is a good thing. It is still possible that she could have some breathing issues, and trouble mantaining temp. They will prob look at her heart and head, just as a precaution so don't let that worry you.