Welcome to FT!
This type of situation reflects horrendous customer service, not age discrimination. I would let Continental know about it, but would not mention the age issue, since there is nothing in your original post to indicate that the agent was rude to you because you look young.
Your reaction (Me: " OMG , you ARE SO RUDE. Is this how you treat your elite members? That is unacceptable.") did not help the situation. Yes, it's frustrating. Yes, the agent was rude. But your response smacks of "DYKWIA?"
Mike