I would starch it and iron it to get it to lay flat and smooth. Good Luck.

Definitely iron the fabric, but DO NOT use steam. Steam allows the fabric to stretch a little and may knock the pattern out of line just enough to make it impossible to line it up. DO use starch, tho.

I do not cut my fabric until I have ironed all wrinkles and fold lines out This prevents me from having squares and triangles that are out of shape.

Wash, dry and iron.

I washed and ironed all my fabric before cutting my one block wonder because I hadn't been told not to and I hadn't read the directions first - oops. I used pins to line up the pattern, and my cutting was quite accurate. The blocks are turning out beautifully.

Looks like you've got your answer. Just to add my two cents worth, I always spritz with starch and iron my fabric. It is smooth and easy to work with and no wrinkles to mess up my cuts. I can do that all by myself.

You will be much more accurate in your cuts if you iron it first. Especially if you are cutting on the diagonal

I'd iron it and I would also use a lite starch or finishing spray. The fabric will be much easier to cut and to work with.

Imho , ironing fabric is one step that should not be skipped. I have a friend that doesn't iron her fabric or her blocks and they just don't look good. Never skip the iron.