I would guess it's not too long a time between the funeral and baptism. We know Connie has already had her baby at the time of Vito's death. Even assuming the family had a mourning period before the christening, it probably took place within 6-8 weeks at the most.

Apple

A wise and frugal government, which shall leave men free to regulate their own pursuits of industry and improvement, and shall not take from the mouth of labor the bread it has earned - this is the sum of good government.

- THOMAS JEFFERSON