Rare but it happens.
I saw 3 at DAC (agency - not an AMP) last year.
But they come in and out very quickly, so you have to check the site and the reviews.
Age is very often misrepresented, so it is best to check reviews of guys whose opinion and judgement you trust.
Of those 3 that I considered, in my judgement, to be early to mid 20s, one is on schedule today.