I played off center with trumpet?!

I played off center with trumpet?

and i am working on fixing it....i need some exercises or something to get used to playing in the middle so can anyone give me some advice?

Your mouthpiece placement, especially in the horizontal regard, could not be more inconsequential. Roughly half of all players play off center, usually because of the positioning of their teeth. Maynard, Jon Faddis, etc. do/did just fine without their mouthpieces perfectly centered. After extended practicing your mouthpiece should naturally end up in the most efficient location for your particular dental setup. There are no exercises that teach you to play on a certain part of your lips. However, to find what the ideal part of your lips is, I'd recommend long tones/flow studies (Anthony Plog Book 1) and a Herbert L. Clarke Technical Studies book.

If you can't tell, I too play trumpet. It's a wonderful instrument, but demanding. If you have any other questions feel free to ask.