Sorry but that seems unrealistic. It becomes tougher and tougher to cut off a minute, so I would aim for something realistic like sub 23-24
To quote Kanye West, “Aim for the stars so if you miss you land on the clouds”
But setting yourself unrealistic targets will just demotivate you further. Sorry to say but cutting down 5 minutes in a year is a ridiculous target and it won’t happen. Focus on cutting down to sub 23 first, that’s still a good time