As we all know flights out of NYC don't always run to schedule but the best advice I can give you:
1. Try not to let it get to you in advance too much - there are too many hypotheticals that it will just make you anxious over something, in the end, hundreds of our customers book every day.
2. The flight is blocked at least 30 minutes more than than needed. Flight sometimes get airborne 1 hour after scheduled departure time and arrives early.
3. You will land in in terminal 2E and probably leave out of 2F - they are right next to each other. You show your passport and have a quick security check and you are literally right at the connecting arrogare.
4. Weather affects all and it's a shame you might have industrial action to deal with as well. Seems like domestic French flights are suffering most. Longhauls are fine and Europe didn't seemed cancelled out too badly.
5. If you are staying in Rome for at least a night, try to pack two outfits that will fit into you carry on so in case baggage delays are occurring you will be a step ahead.
6. It seems you are originating out of IAD so less weather to worry than the NY airports. Just get there a bit early.
I'm sure you will have a great trip - but you are right to mitigate potential bumps.
Safe travels!
Adam