It's going to take you awhile to quilt that and you want it to be a pleasant experience! I would rip the quilting out, gently hand wash and air dry, then quilt.
Another option is to spot clean it then put it in a low-heat dryer for a few minutes with a fabric softener to air it out and freshen it up before ripping it out and re-finishing it.
Either way, if you want it at it's best you should requilt it.