I am pretty sure you can have any size pantry you want?

But I need it to not be crowded and I'm concerned about the 5.5..

Crowded with what?

It depends on how deep of shelves you want or the size of your building lot, which ever comes first :). Standard shelf depths are 12", 16", & 24". For instance, if you put a 24" deep shelf on the back wall, a 16" deep shelf on one side, and a 12" on the other, you end up with better storage. Deeper isn't always better because things just get pushed to the back and forgotten. You might also consider a can rotation system.

I agree with Fred S;)

Thanks Fred!!!