hi i too have no 2 on the way and will have a 20 month age gap. I do go to playgroup where all our 1st bubs were born within 8 wks of eachother and all 1st babies. There are currently 5 of us pregnant with our no 2's. i have found this very comforting as we will all be a good support for eachother. maybe you could look in you area for something similar. My DD when asked where is "our" bubba will point to my tum and kiss it. I work PT at the min with 6 wks to go so when i finish work we will get the new nursery ready and try to make her aware as much as poss that we will soon have a new addition.
I also have a close friend who has a 6wk old and a 21month old. She has said that her first 48hr out of hospital where the hardest so her mum stayed with her so bub no 1 had all the attention he needed and "wanted". He has adjusted very well and she has had no further problems. My DD see's her new one often and is very good with him when around. I guess we will have our share of ups and downs but i am looking forward to seeing my DD with her new sister.