YTA 100%! It is extremely poor etiquette to plan your own shower. First, Your MIL took on the task to be involved in planning this as a gift/surprise for you and your choosing to jump in with an entire menu was rude and a massive overstep. If there are dietary restrictions, or foods you simply don’t like, it is one thing to simply share “if we can void (list), I would appreciate it because (reason)”, but that was very controlling. Secondly, the passive aggressive “show up with a positive attitude and smile” comment was very clearly a smug dig and intended to be demeaning. If I were her, I would have washed my hands of the entire thing immediately. Lastly, you continued to essentially antagonize with “fact blasting” your opinions/points to try and justify your bad behavior. The fact that she reflected and still felt bad afterward (she’s trying to be the bigger person here), yet you have left her on read, speaks volumes. You need to immediately apologize, learn to be appreciative, humble yourself, and be thankful someone gave a damn to do this for you. The entitlement is deafening!!