I am not sure either, but I think so. I remember that I used to watch a lot of DVDs and TV cassettes that had a lot of different movies or cartoons. I remember my grandma's had a couple of pokemon anime and a pokemon movie, maybe. SO yeah that was my first anime but def not my first cartoon. The episodes were old, they were still in Kanto but I was playing Pokemon Diamond for the first time and I remember I was super confused because the gym leaders didn't mach. I was like: "wait what? but that isn't a gym leader!" lol.
Then later when I started watching cartoons on the TV, it was already Pokemon Diamond and Pearl arch but that happened like a couple of years later, maybe. In the meanwjile I started watching some other anime too, the famous ones lol. Mainly Dragon Ball tho. Some Naruto and One Piece. Ngl, those ones got me more than Pokemon. I liked the anime and watched almost all the Diamond and Pearl arch and the movies, then slowly with gen 5 anime I got a bit less interested and I stopped following it. I watched just the Unima League episodes and then the first episodes of the X and Y arch but like after 3/4 episodes I stopped again. The last episode I watched was the final episode of Ash in the Kalos League, because they created much hype about Ash winning. Idk why, but I always kinda liked the League part of the anime. However, there was a time, when I was about 12/13, (before X and Y, I think) in which I was a lot into the pokemon anime, but not the current episodes but the older ones. I had a device that could record the episode so I did that daily, because it was on while I was at school and when I came back I used to watch it. It was the Jhoto arch.