-Super Mario 64 is an excellent game. I played it on Nintendo Switch(haven't finished yet, think last time I played I had around 20 stars or something...) I also haven't played that much N64 games before in my life, but based on what I've played before, I would suggest Mario 64 as a first Nintendo retro game to play, more than Zeda from N64.
As someone who played Ocarina of Time almost 30 years after its release, I must admit and say that despite acknowledging that it must have been a nice game for those who played it on release date, I didn't enjoy playing it so much in modern days . The graphics felt "outdated" in an unpleasant way ( well, for obvious reasons, since it's a Nintendo 64), the camera was terrible( Super Mario 64 still has a somewhat annoying camera for current standarts of gaming, but still feels better), and the animation doesn't look as fluid as Mario 64.