I'm guessing mid to late 60's, here's why... That yellow fabric with the flowers just above the red plaid in the second pic and then again on the left side of the same pic. My mother made my sister and I matching dresses for school from that exact fabric! I remember it because my sister hated it when we wore them on the same day (I made sure to get dressed after she did so that could accidently happen, A LOT. We had several matching dresses LOL). I think I was in the 1st or 2nd grade. Mom has a picture of us in them, I'll see if we can dig it up.
Its a beautiful quilt, what a treasure Ruth...so glad you rescued it!!!