No problem, I understand.
However , most 3 gun matches are designed around moving and shooting, if you understand going in that you will be at a great disadvantage, you can still shoot the match.
just as if you joined a one on one basketball league, you may be the best 3 point shooter that ever lived, but pretty good chance your not going to win, that's the nature of the game it requires agility and movement.
There are shooting competitions where movement is not required, they may be more suited to your abilities.