MIL lives in a different country, usually spends Christmas with her siblings and their family.
First Christmas this year with our baby, wanted it to be just us as a new family to start traditions etc
MIL brazenly said on the phone the other night that she will be coming and spending Christmas with us, no consideration for what WE wanted to do, she will come and stay in our house and have the day with us as a family
AIBU for thinking this is incredibly rude to impose yourself on your son's family and have no consideration for what plans we might have had.
(For context she is absolutely mental and we don't really get on that well, she doesn't even get on that well with her son.. so it's not even going to be enjoyable having her here)