grammaticality - "I and others" or "others and I"?

I have traditionally learned that a first-person pronoun should always come last in a list, e.g.

Bob and I found this to be interesting.

However, it sounds awkward to me when this rule is used with 'others':

A couple others and I found this to be interesting.

I would be more inclined to go with:

I and a couple others found this to be interesting.

Which sentence is (more) grammatically correct?

Answer

They are all grammatical. Whether or not you put yourself first is a matter of etiquette.