Photo - I unfortunately have no experience with a difficult MIL - but I do have experience with people.
You sent flowers, which was truly a kind gesture. Let's see what happens. She also spoke with you about things she'd never disclosed before - I don't know, but that kind of sounds like a thaw to me.
Just like with DB'ing, trying something new never hurts. If it works, great! If not, don't do it anymore.
