The use of the words was or were after an if can stymie even the best of writers and speakers. For years I would simply try to find other ways to say it, avoiding the embarrassing dilemma altogether. But I’ve learned an easy way to remember which to use, and I’m passing it along:
Use “if I were” if you are talking about something that you long for in the future or present. In other words, if you can wish it or dream it, use “were.”
“If I were rich, I’d get a new iPhone.”
“If I were president, I’d balance the budget.”
Use “If I was” when you talk about something that was true or could have been true in the past.
“If I was at the party last night, I don’t remember.”
“If I was late, I am sorry.”
It’s all about future wishes vs past reality. Sort of. If I were you, I’d keep that in mind!