I typed a lot but soon realized that you are asking for a flight from New Jersy to Florida, a 2.5h flight.
Just my humble opinion as a childfree person:
First of all, congrats on your new baby!
The noise would not bother me. Being a parent is not easy, especially when traveling with an infant.
Also, a 2.5h flight within the US, I personally wouldn't think there's that big of a difference between economy and first class...
Again, my opinions are my own.