When someone says, "You look similar to X," and you are certain that you are younger than X, you can respond politely and playfully to clarify the age difference. Here are some potential responses:
"Thank you! I take it as a compliment, but I'm actually a bit younger than X."
"Oh, that's kind of you to say! But believe it or not, I'm younger than X."
"Wow, you think I resemble X? Thanks! However, I'm the younger version of that resemblance."
"I get that a lot! But don't worry, I'm a few years younger than X."
"You're not the first person to mention the resemblance! But just to clear things up, I'm younger than X."
Remember, the key is to respond in a lighthearted and friendly manner, making it clear that you appreciate the comparison but want to clarify the age difference. Humor can help make the exchange more enjoyable for both parties.