Being the youngest in the room doesn’t disqualify you. Being the least prepared does.

Age is the thing people notice first and stop noticing quickly. What actually determines whether you are taken seriously is whether you know the material, and that is available to anyone willing to do the reading nobody checks. Being underestimated is even useful, provided you have something behind it.

Walk into the next room where you are the youngest having done enough homework to be the person who knows the specifics. Bring one prepared question rather than trying to sound senior. Competence is the only thing that settles the age question, and it settles it immediately.