Should i use _n for pronouns in translation?

It’s interesting idea and I think that such approach will work for you. What I would recommend you is that it will be better to use constructions like this:

// $singular = 1 - for 'me', 2 - for 'us'
$like_on = _n('Like me on %s', 'Like us on %s', $singular, 'my-plugin');

In this case it will be easier to understand how to translate the phrase.

Also read this question How-to: Translate plural forms for themes/plugins with PoEdit to understand how to configure your poedit to support plural forms with WordPress keywords (like _n, _n_noop, _nx and _nx_noop).