Placement of 私 in a sentence

Question

Are both options grammatically correct? 家族の中で私が一番背が高いです。 私は家族の中で一番背が高いです。

Answer 1

Yes, all of the following are grammatical (yours are 1 and 3).

1. 家族の中で私が一番背が高いです。
2. 私が家族の中で一番背が高いです。
3. 私は家族の中で一番背が高いです。
4. 家族の中で私は一番背が高いです。

I don't feel any difference between 1 and 2, but 4 may be slightly less idiomatic than 3. A rough idea is that it's better to put the topic first.

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The following question will help:

• What's the difference between wa (は) and ga (が)?