The Baggies face Brum this weekend.
Carson told the Birmingham Mail: "I was pleased to no longer be a footballing nomad (at Liverpool).
"I made the right decision and I'm sure Ben (Foster) has as well.
"He wasn't getting much football at Manchester United and at our age you need first-team football, not to be a third-choice goalkeeper as he was or out on loan like I was.
"It would take three or four months to settle down, get to know the area only to then find yourself moving on.
"This move was important for me, as I'm sure it will be for Ben once he's settled in properly at Birmingham."