Is that ok to wash the new fabric before sewing?

Depends if it can shrink, I never wash before I sew...never a problem.

yes , if it is washable fabric. Then lightly iron so it is flat.

If you are going to be washing the item after it's together it's best to prewash the fabric just in case it shrinks. While it is still damp run an iron over it.

If you wash before sewing you take away the risk of shrinking your garment or whatever you are making. Always wash before sewing!

Not only is it ok, it is the desired thing to do.

Yes, as long a it washable. Simple trick to keep all of that loose thread from tangling up; snip the corners of each piece about 1/4" -1/2". On an angle . It will keep it from fraying. Hint: use Color Catchers Sheets ( in the wash supplies isle) Wash on casual/warm water.

Unless you will NEVER, EVER be washing the fabric, it is always best to prewash any fabric that you plan to sew. That way, it eliminates the possibility of shrinking. Once washed, it is a great thing to iron it so that it is nice and flat when you pin your pattern pieces to it.

I used to soak the material in water & vinegar before washing and then sewing. 95% vinegar. Kept colors from fading. Still nice & bright today. 15 yrs. ago.

My mom taught sewing classes, and I started learning to sew at age 9. I would never sew fabric without washing it. After washing make sure one end of the fabric has a thread that goes from finished edge to finished edge. When you fold flat the corners of that end should be aligned. If they aren't you can stretch it back into shape by holding the shot corner, and the corner diagonally opposite it and tug a few times until even when folded. If you have very much fabric you'll need someone to help with this process. Good Luck!

I would highly recommend washing it first, because if it shrinks, the stitches will be too loose.

I was taught, years ago, in home-ec class, that you should always wash or at least wet and dry fabric before sewing. This was to make sure that any shrinking was done before the garment or project was made. If you don't do this and the item shrinks after you put all the effort into making it, you may not be happy with the results.