If I were...

More people should use the subjunctive, because it represents hope and possibility instead of the binary modes of truth and falsehood. "If I was younger" is an ugly expression. It confuses you. You were younger once, so the "if" expression always evaluates to true, even though the intent of the sentence suggests the opposite. This is poor English, and poor communication. It does not clearly convey your idea.

Instead of this tinlike expression, use "If I were younger", "If I were home", "Wish you were here", etc.

If you're ever in doubt, invert the expression to test its grammatical correctness. "Were I younger, I would...", "Were I home, I would... ", "Were you here, we could..." and so forth. "Was I younger, I would ... " just rings leaden in the ear and illustrates how ugly the misuse of "If I was younger" types of expressions in absence of the subjunctive really are.

Finally, the subjunctive opens the door to an even more poetic grammatical device, which I would see spent into common circulation again in the next century: the optative. It is exemplarized by John Keat's

Bright Star! Would I were steadfast as thou art

"Would I were younger" is more than just a description of a hope or dream, but an explicit statement-act of hoping or dreaming. "Would I this nation were at peace". Now that's beautiful. Try saying the same thing using the ugly non-grammatical English from above.

"I wish this nation was at peace."

Guess what? It was! So your wish came true. Try again.

"I wish this nation was at peace again"

We have been at peace many times. Try again.

"I wish this nation would be at peace"

We undoubtedly will at some distant point in the future. Try again. Hopefully I've expressed the practical utility of using these proper grammatical forms. Dream big. Conjure the subjunctive and optative in your writing.