A) What your first Pokemon game was?
First Pokemon game I played was Pokemon Diamond when I was around 8 or 9 years old on an R4 card. At the time, I thought pokemon was stupid and didn't understand why it was so popular. However, when I invited my best friend at the time, I let him use my DS and he played Pokemon Platinum on the r4 card. He managed to convince me how fun the Pokemon games were, but didn't want me to play Platinum on the R4 card because he got quite far in the game. Luckily, I had Diamond on the same R4 card and he told me to play that, as fundamentally, Diamond and Platinum are the same games. After that day, I played Diamond for almost 8 hours straight daily because of how fun the game was at the time.
B) Is your first game also your favourite game (if not, which one is?)
Nope. After playing Platinum (my friend let me continue his adventure since he couldn't come over to my house as frequently) I started to notice a huge amount of issues in Diamond, such as the ridiculously slow Surf speed, lack of Pokemon, etc. Platinum was a damn good game and fixed a lot of issues Diamond had, but still wasn't my favorite. I would say my favorite Pokemon games are either HGSS or Black 2 and White 2.
C) Anything funny you did when you first got the game cause you were new to the series?
In battles, I only trained my starter. I didn't really care about the other Pokemon in my party as much and almost never used them. I was able to steamroll through most of the game this way, but the fights against team plasma admins, as well as certain gym leaders very hard. Because I was also playing this game on an R4 card, I hacked the game after I caught Dialga and leveled every Pokemon in my team to level 100. I was then able to steamroll through the elite four with no issues. I also was able to activate all the mystery gift event despite my DS not being connected to wifi at the time.