I saw Star Wars (before it was called "Episode IV") but not quite in its first run. It had finally finished its main run after many months and finally got to my local $0.99 theater, where I finally got to see it. I loved it. I was about 11 or 12, depending on the date. I had followed all of the hoopla, and I had really wanted to see it; but my parents did not care for sci-fi, so I did not get to see it until it was cheap and maybe they were tired of hearing me ask.
By the time it was re-issued the next year, with "Episode IV" added into the crawl, I was all-in.
One cool thing to note that not many people know is that it was marketed in 1977 in smaller theatres, even when bigger ones at the same complex were available, because the "sold out" and long lines in the news added to the "must see" factor. I remembered that, even thought I could not go, it was always advertised as being in "Ridge Cinema 3" locally of our four-cinema Ridge Cinemas complex. Later I realized that Cinema 3 and 4 were small, and Cinema 1 and 2 were much larger (even double in the case of Cinema 1). [Back in those days the newspaper ads for the movies usually told you which actual cinema within the complex was showing your movie.] So, later on I was really into movies, and as remembered that I actually later had the occasion to ask the manager and they were able to confirm that, yes, that had been done on purpose. It was a directive from the distributor, to keep the "sold out" driving more demand.
By 1980, however, that had gone out the window, and "Empire" (which we called it, not "Episode V") opened in the biggest cinema wherever it played (including Ridge Cinema 1).
And, yes, we called the original trilogy by names, not numbers:
"Star Wars"
"Empire"
"Return of the Jedi" (which it was rumored was originally going to be called "Revenge of the Jedi" until it was determined that "Revenge" would not be an appropriate title for what Jedi would do).
We knew that they had numbers, but we never used them, and we most certainly NEVER called the original "A New Hope." We usually just said, "Star Wars" or "the original".
And the phenomenon around the original was amazing for at least a full year. It was everywhere. You could not escape it. And, yes, there was a backlash also. There were kids who were proudly defiant, saying, "Yuck. I have not seen 'Star Wars,' and I don't want to.' "