Unrelenting issue

My husband and I are building a house in Tennessee hopefully soon, and we're hiding it from our kids because we want to surprise them later when it's done.  However, one of our kids (35 years old with a 4 year old) moved with her family there last year and want us to move there to be close to our grandson.  Well, we planned on moving there long before they decided to up and leave near us in Illinois.  They're pressuring us to move there and we keep saying we're looking but not finding what we want to hide the surprise.  Our daughter is so upset with us and pretty much claims we don't want to move and that it's upsetting her 4 year old and putting us on a big guilt trip and blaming us for everything.  Now we don't know when we can even facetime with him because she is putting us through this again with twisting stories on us. We didn't even start this garbage but now she doesn't want to talk for a few days as it's too much drama and it will affect her health and the unborn baby.  The sad part is that we didn't start this and she's making it look like we did.  She's done this many times.  The funny part is that a few months ago, she told us we have to come the month that the baby is due to watch our grandson.  I'm at my witt's end with this.  I hoped she would act like a grownup by now