Spray skirt too tight to fit kayak cockpit
They are very tight initially, like a wetsuit, because neoprene stretches a lot with use and you don't want water pooling on the deck. So to speed up the loosening, wet the spray skirt and put over the cockpit, and leave for 48 hours. This will help stretch it out. Alternatively you can soak the spray skirt in fresh water overnight, which will make for easier putting around the cockpit lip.
Here is a link on how to best attach your spray skirt to the kayak: