10% of full fare F will cost ya...

If you booked your trip just for the sake of enjoying travel in F - just cancel it.
You will not be able to relax or sleep much as you will be constantly on the edge of your seat expecting baby to wake up demanding food, change etc...
And if flying ends up causing any sort of discomfort to your kid - may god have mercy on you and fellow pax in F... All after paying $2K for the pleasure of adding lap infant..

If want to visit those destinations, travel with an infant is doable and premium cabins make it tolerable. It is indeed easier to do it at 3 mo vs for example 1 yr.