Carbon bike vs Aluminium with upgrades

Shopping for my first road bike, my LBS has floated the idea of getting a carbon bike to start. I’m pretty resistant to the idea because it is about $1000 more than the aluminum model. I was looking at and way out of my budget. I hear the advice that carbon bikes are smoother, and I will eventually want to upgrade to it. is it worth the upfront investment or is that money better spent on nicer wheels a few years down the line? Currently debating between the Specialized allez sport, cannondale synapse, and specialized robuiex. Budget is $2000usd