I am currently grinding for sub 21, which I am mostly sure is possible. You just need near godlike RNG.

Today I played 200 games of FTTBA, and found how often each time showed up. Here are the results:

21s: 8.5% 22s: 39% 23s: 46% 24s: 6.5%

Another fact: Franklin the Turtle's Balloons Away is the greatest speedgame of all time. You will never be able to convince me to speedrun another game ever again.