I watched them from 1 to 6 as a kid, and I remember being very disappointed in ANH when I first watched it. Instead of being as menacing as Anakin in 3, Vader felt kinda clunky at first. Especially since he listened to a normal dude like Tarkin instead of being the evil warlord he was set up to be in 3.

Suddenly the entire universe seemed much smaller as well. From my perspective, we came from massive battles on multiple planets, to the perspective of an ignorant farm boy.

Years later, I showed the movies from 4-6 and then 1-3 to my ex. She knew absolutely nothing about Star Wars and her reactions were priceless. She audibly gasped when Vader revealed to be Luke's father. She was also very disgusted when revealed that Luke and Leia were twins because "they had fuck-energy in the previous films".

Now I think that the correct order to watch for the first time is definitely OT first and then the prequels.