Capitalizing the letter "I" is an important grammar rule. In English, the pronoun "I" is always capitalized, regardless of its position in a sentence.
Incorrect: she and i went to the store.
Correct: She and I went to the store.
Incorrect: he said that i could join them.
Correct: He said that I could join them.
Incorrect: we saw a big i in the book.
Correct: We saw a big I in the book.
Remember, capitalizing "I" is a simple but important rule in English grammar. Always remember to capitalize "I" when referring to oneself!