My 15 year old watched one baking video and now supervises my sponge cake

I have been making the same sponge cake for twenty years. Last week she watched one video, and today she stood at my elbow saying 'you're overmixing, Amma' and 'is that oven preheated or are you hoping?' The cake came out fine. She said it was 'a little dense, but good for you'. I have been told to fold.