I loved that game when I was little
This Pokemon game takes place in the region of Sinnoh. Like all the Pokemon RPG's, you go out and catch Pokemon and try to beat the Elite Four and become a Pokemon Master. Some other stuff happens I guess. I dunno, I was busy catching cute Pokemon.
First you pick your male or female hero, and then you get a choice of three starter Pokemon of grass, fire, or water type. The choices this time are between Turtwig, Chimchar, and Piplup. I of course chose Piplup. Afterwards you go out and fight Pokemon to gain EXP, which will allow your Pokemon to get stronger, learn new skills, and maybe even evolve. You can also catch Pokemon by weakening them and throwing a Pokeball at them, after which you can name them and train them. Then you go around beating gym leaders and collecting gym badges, with the end goal of battling and defeating the elite four.
You've already heard part of this story. I wanted to play Pokemon games since forever and ever but life didn't let me until I lived on my own. Even when I was younger and had consoles, the man I was living with wouldn't get me a handheld because he said they were a waste of money and you couldn't see anything on that tiny screen anyway. Much sadness. But eventually I saved up and got myself a DS Lite and Pokemon Diamond. It was my first Pokemon RPG and I was super happy with it. I had stopped watching the show by that point so I didn't know who a lot of the Pokemon were, but that made it kind of special because every new Pokemon was a surprise! Overall I've had a lot of fun with Pokemon Diamond.