Daughter due 4 days before Son turns 2 years old

No idea what to expect, really nervous. Suggestions or ides to make this easier?

Maybe give him a party early so he won't feel left out? It will be even harder if he reverts back to being "babyish".

Good luck lol my 2nd baby is due when my daugter is 15 months old.  

My bf (not my son's dad, but my daughter-on-the-way's dad) suggested I alternate which child gets their bday party first that year, and my grandma (my children's great grandmother) said she brought home a present for her son when her daughter (my uncle and aunt) was born, saying it was "from the baby" because (in her words) who can hate someone new who shows up to meet you with a gift for you! So nervous that he's gonna be super jealous of Amelia when she's here...Although, I tell him that his sister is the one kicking him thru my belly and he loves to play with her in there. Alexander also seemed so happy to hear her heartbeat just a week or two ago when he came with me to my appt. Could this be him understanding what's going on and him showing he's ok with it or mearly coincedence?