First, your numbers are totally off. If the entire box is 32", and your port is 3", that leaves the front of your box at 28.25" and an internal width of 27.5. If the outer depth of the box is 18", that leaves you with an inner depth of 16.5". If the left side is 14.25, that only leaves you with a 1.5" space between your baffle and the back of the box. Not sure if you really want to do that. If you go with the 14.25, though, your internal volume in front of the baffle not counting the speaker displacement is 3.288 cuft, so that would still leave you with 2.938 cuft.
If you make sure you have a full 3" behind the baffle, that drops your 14.25 side down to 12.75, so your total internal volume minus the .35 displacement of the woofer is 2.59 cuft. I've redrawn your design in paint.net. I'm not sure you really want a 14" gap on the inside there, since the drawing doesn't doesn't look like it should be that, so I'm assuming you actually wanted something more like a 3" gap, so that's what I went with. I think if the gap was 14" you'd have some additional volume to account for.
