Normally, people will feel less stressed and will share more comfortably when being interviewed by someone younger than themselves, this is also an advantage for you.
How to interview older people
You want to appear mature from the start, but not too old or intolerable. Therefore, you should take advantage of your age to do that. Before the interview begins, you can talk about a TV show that both of you are interested in to create a relaxed atmosphere that helps reduce stress for both of you.
Refer to the article on interviewing skills to be able to handle situations that occur during the recruitment interview.
Don't mention your age or experience
Remember that the person you are interviewing will probably not know your age. And even if their first reaction is why you're so young, they'll respect you if they really want to take the job - unless you don't respect yourself.
In other words, don't make your age the center of the interview. When you were sent to interview someone, your manager or supervisor certainly believed and thought you were the best fit. Do not forget that.
In short, interviewing someone when they're older than you is stepping the line between empathizing with the candidate and not making age the focus of the interview. Remember, age is just a number and it doesn't determine anything in your career. Hopefully with our tips above, you will have more confidence when entering an interview where you are the youngest.