Hi Warrior, and welcome!
You've competed in 4 Pokemon Video Game Championships? Lucky you, people from my country can't even participate (sob) but I have to say, the battles get very heated in those competitions over there. Do you have any fave strategies in competitive battling? Any favorite tiers? Anyways, PC has its fair share of battlers so I'm sure you'll get on well in our battling community well.
As Gyardosamped said, you should check out our Battle Center forum to discuss all things competitive battling, and we also have a Pokemon Showdown server where you can battle and chat with fellow PC members. I'm a regular on the server, under the username OshyHikari. I hope you'll be able to take part in Community Day there at the end of March, it's very fun and I enjoyed the last Community Day around Christmas.
I'm Hikari, and feel free to VM me if you need anything.
- [supporter]Hikari10[/supporter]