Congrats on your new rig. I had a 2017 ACE 29.3 and while I had it really enjoyed the unit.
I would make sure you have some type of road side assistance program. Be it Good Sam, FMCA to name a couple. Stay away from the dealer add on's it will cost way more than they are worth.
I would however pressure the dealer for free things like sewer hose, water hose and maybe an extra electric cable.
Do a very good in depth PDI walk through. Get to understand how everything operates. Pay attention to how to winterize the unit where the water heater bypass values are. One of my values was behind a partition. Get to know the importance of slide operation.
The most important part is take it use it and enjoy it
Good Luck safe travels