The first time was on neighbor's TV. I was 7-8 I guess at that time, I distinctly remember watching it till Quiditch match, it was good but didn't do much for me. Then for some years I had some encounters with it and watched few rip-offs like there was a Star show, something something magical school, with four/seven pillars to protect the school. IDK, it's bit fuzzy. I used to wonder why the **** are these Potter films so famous.
Anyhow, in the summer of 2013. Me and my friends used to have an argument, Hollywood vs Bollywood. I used to be on Bollywood side, having watched may be 10-15 Hollywood films till then. So one of my friend suggested me to watch Harry Potter. He gave me all the films in franchise and so started my watch.
And boy I was impressed and you know the rest.
Since your post is just for first film, well it was mostly familiar till the Quiditch part, and then it was fun. Since I was just 16 and new to Hollywood, I couldn't get any flaws in it, and now I am too blinded to look for any. So these films are my innocence. I always love the fantasy genre, Harry Potter was the King of that place in my heart, until GoT 2nd watch happened.