How do you let you mum-in-law know that you will be calling the shots on the upbringing of your child (without sounding rude)?

...take all the advice, note them up then apply as needed. You might find some useless at the moment but might be helpful in the future-- remember old people do have wisdom to share bec they literally been through all before us. haha Instead of focusing on "who's who" channel both your energy on the child --give love, attention and harmonious environment to live in.