I would like to thank Trenbeathranch for sharing her knowledge to teach us that are not in the know. That's how all of us learn. I'm a newbie so I learned a lot from her explanation and will now be careful with pressing.
It looks to be a beautiful quilt. Please post pics of the entire quilt. Not knowing your MIL my quess would be that she is going to appreciate your own thoughtfulness and hard work. Thanks for asking the question and not keeping it to yoursel so we all had the chance to learn.