I see. I was the same as you. I had only watched snippets of series 1 and 2 at the time of their airings, but it wasn't enough to make me be interested, despite all of my cousins constant recommendations. Besides, I was too invested in Timebomb and BB17 to care about LI.
It was only during series 3, when the show was at its peak ratings wise and everyone talking about it, that I had decided to watch it. It was 2 weeks into the series that I started. I was hooked after a particular talked about episode, and like yourself, I had decided to binge watch all the episodes the following day.
After series 3 ended, I went back and watched series 1 and 2, and I've loved this show ever since.
I have to say I loved your enthusiasm for Love Island this year. Despite it being your first time ever watching, it felt like you were a regular long time watcher.