I want to know what differences are among these expression

Question

What are the differences between these three sentences?

1. I went to school and I ate my lunch in 3rd class.

2. I went to school and my lunch was eaten by me in 3rd class.

3. I had gone to school and ate my lunch in 3rd class.

Are these sentences correct? Are there any differences between the meanings of these sentences? If there are no differences, why might one sentence be used instead of another?

I know about the passive voice and the past perfect, but only enough to pass an English test. I don't have much practical experience.

Answer 1

(Note: I'm not a native speaker, too.)

I went to school and I ate my lunch in 3rd class.

Something used in casual speech / online chat.

I had gone to school and ate my lunch in 3rd class.

A tiny bit more "grammatical", probably used in formal writing or in books or on English exams. But I guess it's not much different from the first one.

I went to school and my lunch was eaten by me in 3rd class.

The passive voice is probably justified if your lunch is the main subject of your talk, or if your lunch were eaten by someone else - "I went to school and my lunch was eaten by evil squirrels". But if you're just talking about your day, "my lunch was eaten by me" sounds a bit over-dramatic.