How much my (previously perfectionist) housekeeping standards would slip - I'd never expected to be patting at the latest wee/milk/sick wet patch on my bed at 4am and deciding just to put a towel down over it and sleep on top. (I'd never expected several good mattress protectors to be quite as essential as they are....)
I didn't expect to have, in the first few weeks, terrifying intrusive visions (like flashbacks) of DD getting hurt in some way - I'd be feeding/minding my own business/eating/whatever and suddenly experience a terrifying vision of DD falling or being dropped and her skull smashing or similar. Now I know that this is TOTALLY NORMAL and every mum I've spoken about this to has had the same thing - it must be some kind of evolutionary adaptation to make you protect the baby - but if you're already sleep-deprived and feel out of control it's very scary.
How much I would like spending my time saying silly things out loud like "tummy to mummy, nose to nipple" at the start of every feed, or "where's that burp? THERE'S that burp!"
How much my relationship with my mum would suddenly improve.
How much I would enjoy singing all the songs to DD that my mum sang to me.
How much cake I could eat (have never had a sweet tooth in my life until I was pregnant - I have got monstrously fat just eating cake and chocolate since the birth...)
How difficult the first couple of months are - OR how quickly you bounce back as soon as you get a bit more sleep and readjust. In the first few weeks I genuinely thought my entire selfhood/life/mental peace had vanished forever - now a few months on I feel pretty much back to the old me (though substantially fatter.....)
How weird-looking newborns are, but how quickly they transform into the most adorable baby you've ever seen.