Hi ori,
Sorry, I can't speak for the Infinity but was just aggog withe the N.C.L. Wind.
My girlfriend is also in a wheelchair with Spinal Muscular Atrophy. She has a fully automated "Bomb". 350 lbs of 'tank'. Very fast and very manoverable. I took her on her first cruise, my 11th, aboard the NCL Wind to Alakaand every port was grreat. Getting on and off the ship was easy and the ship itself was entirely accessable.
The NCL Wind was a thoroughly enjoyable experience and has turned her into another cruise-a-holic.