Congratulations, I fell pregnant after being told there was no chance when my DD was 6 months...
It has been so much easier having them so close in age, don't let people scare you,
benefits are, they are usually at the same stage so no carrying a tired baby to toddler playspaces, or older childrens parties,
once the youngest can crawl they are fascinated with each other and entertain each other constantly, mine are now 9 and 10 and l would do it again in a heartbeat, they still play together all the time, so little pressure for endless organising of playdates.
They want to play the same sorts of things as they are at the same stage.
Advice, Get first one into a good sleep routine fast! I found Gina Ford brilliant for my premie DD, she was sleeping 10.30 till 5.30 at 4 and a half months, and with totally predictable daytime naps.....that was a lifesaver when l came out of hospital with another c-section.
Be really organised before number two arrives, freezer full of food, cleaner if possible, online food/nappy deliveries, call in favours from friends family if you can.
Enjoy you family, those early years were the best for me..