My kids are 4 years apart.
They are really close and 2 peas in a pod.
The age difference, for ME... was perfect.
My daughter being older by 4 years... and then having another baby around.... it was perfect. Developmentally, for her, too.
She adjusted WELL.... and never had any jealousy. AT all.
She loved her brother very much... and once he was born... she told everyone... how lucky she was.....
From the time I was pregnant with my son, I spent time on my pregnancy...WITH my eldest child, my Daughter. Incorporating her INTO it all... not making it 'my' pregnancy.
We took photos each month with her and my growing tummy.
I talked with her about her baby brother in my tummy.
She held and talked to my tummy and sang 'him' songs.
I took her to ALL my prenatal visits, which my Doctor encouraged, and he even taught her how to use the Doppler heart monitor on my tummy, which she loved.
We 'napped' together... I explained Mommy will get tired sometimes... she understood.
I made everything, including her.
I explained everything, in a way she would understand... about my pregnancy.
From the time I was pregnant... I "prepped" her about it and her upcoming little brother... so that once baby come home.. .it was not a shock to her.
I explained what a baby is/does: that it cries, it wakes at all hours, I have to breastfeed, change diapers, that baby cannot do anything by himself... so MOMMY will do that. I explained, that she does not have to 'worry' if her baby brother cries... that is normal. But Mommy, will take care of him. I did not want her to feel 'responsible' for it.
I ALSO explained: that once she is a Big Sister... that HER things are her things. I do not EXPECT her to share 'everything." Her things are special. That she need not worry. She can decide, what she wants to share or not. Its okay. A child... needs to know that. That is.... important to them.
I also explained: that I do NOT "expect" her to be all grown-up and "perfect" once she is a Big-Sister. That I know she is still a child herself... and to ALWAYS know.... that she can tell me anything and how she feels... good or bad... and that it is okay. That SHE is "still my first baby..." and always will be.... Mommy loves her still... the same.
I also told her, that if she does not feel happy, to tell me that too.
We made up a special 'hand-shake' and head-nod with each other, that we could do anytime... just to 'bond' with each other.... and that even if we were across the room from each other (say if I am breastfeeding her baby brother) that she can give me that knowing 'nod' to me... and that that was "our" way... of acknowledging, each other and that we are 'okay.'
ALL of these things... helped my daughter adjust... to me being pregnant AND to her baby brother, once he came home.
It is PREPPING, the elder child... beforehand... all during the pregnancy.
Thus, my Daughter was well adjusted during the whole pregnancy and when her baby brother came home.... she knew... what to expect.
I had a c-section, and I was in the hospital for 3-days. I also prepped her about that, that Daddy will be with her for that time.... I wrote down my daughter's 'routine' for my Husband.... and they would visit me and call me at the hospital, any time.
all the best,
Susan