Unless it is offensive to work on, I wouldn't wash until it is quilted and bound. It will be stronger then. I wash my 50 year old ones in the washer on gentle with a long soak and a short agitation cycle. An Oxyclean soak didn't seem to hurt the colors any and it brightened the whites.
Yours is lovely. It could have been made by my grandmother. I posted two of hers last week.