Jut because a quilt is old doesn't make it an antique or worth more than the sentimental and cherished value. This is a beautiful quilt top and your quilting saved it. It is stunning. IMHO unless there is provenance with the quilt top it is hard to place worth as an antique. Having it finished and loved is more important than the age of the quilt, imho.
This is now an absolute stunner and I would even put it in shows for people to enjoy.
peace