What are good foods for breakfast, lunch, and dinner?

I really want to start eating really healthy- and I'm starting today. I had a plum for breakfast. Is this a good breakfast? What else could I eat- I only have one plum left so that will be for tomorrow, so what should i have or breakfast the following days. For lunch I have no idea what to eat. Should it be small? Big? And for dinner- What should I have? and what should I have it with? I still young and live with my family so my mom will be cooking dinner- so if it is not the healthiest; What should i do? Thank you guys so much :)