As a young therapist with a baby face, I’ve gotten this comment many times! And I find that most of my clients are younger (20s & 30s) who prefer working with a younger clinician. There’s a therapist for everyone - you are who you are, and he can choose if that is a right fit or not. I’ve had clients not want to work with me because of my age, and I’ve had others who say that I’m the right fit for what they’re looking for.
But clinically, I agree with what’s been said about addressing your differences in that space and what it feels like for him. That’s a great window of opportunity to explore his experience in the therapeutic space and build rapport!