Congrats on getting those first few pieces done!
I see you're using hot glue. I've found that those hot glue seams that squeeze out when you put foam pieces together can be quite tricky to deal with down the road. If you can, test out some contact cement. Nothing water based, so LePage won't work, but something like Barge will hold those foam pieces together nice and strong while not squeezing out nearly as much.
One other tip, keep your blade nice and sharp. Even a new blade will very quickly become dull when cutting floor mats. A dull blade will cause you to get chewed up edges. It's not a bad idea to get your hands on a blade sharpener and sharpen that blade every 5-10 cuts you make. You want that blade to feel as fresh as possible to keep the cuts clean.
Best of luck on the rest of your suit!