Mine are 16mths apart, deliberately as I didn’t want my career shelved indefinitely. It was fine, days out were easy, lots of advantages apart from the house being an absolute tip for a couple of years.
I know a couple of people with less than a year gap with their sibling, they seem to get on well as adults.
It’ll be fine if you want two children OP - after all millions of women have managed with twins, yours will just have different birthdays!