By the time you have said all that, the person who asked you the question is onto his 2nd pint of Carlsberg or has fallen into a coma out of boredom. But this is the real challenge even with long established terms like “real ale”, they have become a phrase of convenient reference.
Two challenges for you, I’m not saying my efforts are that good.
1) describe “real ale” in 30 words. My effort is “A cask conditioned beer with no added gas on service, made from hops, barley, water and yeast with sometimes added natural flavours, typically from small to mid sized brewers”
2) describe “craft beer” using the same word limit. My definition “A distinctive beer, from cask or keg, typically, but not exclusively from smaller brewers. Characteristics include high IBU and atypical flavourings. Traditional base ingredients, but can be nitro’ed.”
Its not that easy.