I was or I were???

I'd say it has to be "was" because you're referring to yourself 'along with three other juniors' is an addition but you're still talking about yourself mainly.

It's was, according to subject verb agreement rule, when u have along with,as well as, accompanied by, including, in addition, they don't change the verb that agrees with the main subject, here "I" is the subject so use was.

The sentence in question is a trifle awkward because it separates the subject from its verb. The answer is "I was" because "along with three others..." is a parenthetical (and therefore non-essential clause), while the sentence's subject is "I" If you wanted to convey some thought about all three of you, you'd be using "we" and the verb would be pluralized.

It should be "was" because "I" is the true subject of the verb. Don't be thrown off by intervening phrases that may have plural subjects. Singular subject requires singular verb. Plural subject requires plural verb.