Cheers. The final is a single game, anything can happen. And you still have the best player in the history of the sport in your starting line-up. You won't get smacked by anyone.
Just to be clear, by saying "nothing special", i didn't mean to downplay Argentina's efforts. But i believe that in the 36 years that have passed since 1986, i have seen better reincarnations of your national team in WCs. Even in 2014, when you had a simple plan (some would say boring, but, who cares), you executed it to perfection and you came one Higuain shot away from taking the trophy to Buenos Aires. But this side may be the one that will go all the way. Another example is Italy in 1994 or Germany in 2002. Nothing special, but they found their talismans in Baggio and Ballack, they based their game around them and managed to play all 7 seven games in the end.
Scaloni has to work on his subs and on his plan when his team goes up a goal (or two) in the final stages of your games. I believe that against Australia he decided to park the bus and then he started to bring on the pitch the main culprits of the Saudi Arabia debacle... and after that the strangest things started to happen. But he also deserves credit for fixing things to make his team highly competitive. That little diamond he tries to create in the midfield has become almost immaculate in terms of positioning. What you lack is creativity on the flanks (i bet that whenever Messi plays his signature pass to the left side, he just closes his eyes and hopes that he'll see Jordi Alba instead of Acuna) and a good finisher to make the best of Messi's work between the lines (you can hope that Lautaro got a boost in morale after scoring the decisive penalty yesterday).
I think you'll go through. Brazil may have more options than you (both in transition and against set defences), but Croatia didn't suit them at all. They even defend well, but one thing they don't do as well as you is regaining possession. Croatia thrives on having possession, they get on the ball and they slow things down knowing that, even if they are a goal behind, they'll get their chance. If they manage to survive being hunted down by your players, kudos to them. But you'll have to convert your own chances and not allow them to stay in the game. Oh, and not drop to a low-block, if you're 1-0 up.
Anyway, keep singing your song. It sounds beautiful, and the lyrics are wonderful.