re: I'm watching Seinfeld for the first time...

The first few seasons are quite honestly not all that great. I consider myself a massive fan and follower of the show, but those first few had to really find themselves. As you said, starting around 3 is when it really grew legs, and starting around season 5 I would contend that there isn't an episode that'd be lower than a 7/10 from there throughout the end of the series.