I think you would need to attach a picture and probably floor plan w measurements for advice

From the Net:

32 inches x 32 inches. This modest square is the smallest standard shower size for a typical walk-in shower. Although smaller than some, it’s also among the most common shower sizes you’re likely to find. The 32-inch width is not usually combined with a longer shower enclosure size. If a shower is 32 inches wide, it’s often 32 inches long as well.
34 inches x 34 inches. This is not a particularly common size. However, it does give a little more room than the 32-inch square, so it can be a good option for a bathroom design that needs to conserve space without giving up too much comfort.
36 inches x 36 inches. The 36-inch width is one of the most common widths. However, showers that are this wide are also generally longer than this square setup. It can be a good choice for a shower installed in the corner of the bathroom.
42 inches x 36 inches. The 42-inch length provides some extra space to move around in the familiar 36-inch width design. This less-common size works well when someone wants something a bit larger in a bathroom that doesn’t have enough room for one of the larger standard sizes.
48 inches x 36 inches. This spacious enclosure is among the most common sets of dimensions for showers. If you are putting in a walk-in shower instead of a shower-tub combo, this may well be what you wind up with.
48 inches x 48 inches. This big square shower isn’t one of the more common designs. It can be tricky fitting a shower this size and shape into many bathrooms, especially those with limited space.
60 inches x 36 inches. The extra length in this standard-width shower makes it a luxury design. But that doesn’t necessarily mean it is exclusive. It’s still one of the more common shower sizes.
Custom Shower Type Sizes
Shower shoppers will encounter several specialty-type showers. Each of these has its own set of typical dimensions.

I don't like a claustrophobic shower, especially if someone finds they bump the walls when they raise their arms to shampoo. I would rather add a bench in the 58" long shower and leave the width as is too.