I can still remember playing it for the first time in 1985. A family friend of ours had just purchased an NES and had Duck Hunt/SMB. I was all of 6 years old and my little brain was just.... floored. I had already played a bunch of games on the Atari 2600 by that point and even some Magnavox Odyssey² games, but nothing was like the NES.
A few days later, my mom drove us to the store and I got my own system. Most innovative software ever imo.
That cartridge wasnt released until 1988 in the US. However the loose stand alones were both released in 1985.
A little fun fact
In Sweden the NES was released on the 1st of september 1986 but the swedish importer (Bergsala AB) werent totally sold on Super Mario Bros just yet so they decided to launch the system with these games: Excite Bike, Tennis, Popeye, Mario Bros, Pinball and Ice Climber. The system came bundled with Ice Climber. It wasnt until May 1987 Super Mario Bros came to Sweden.
As for my answer to the thread, I cant really remember.. I am guessing either Mario Bros or Super Mario Bros in perhaps.. 1988 at some friends of the family.