UK VISA duration of stay

Hello, i have my exam on 21 january 2023. I’m planning to attend academy from starting of December 2022 which makes my stay of 56 days. 1. Since it’s nearly 2 months, are the chances of rejection high?
2. I have accommodation agreement and whether i can explain in my application that I’m planning to join academy from 1st December to 12th December and then practice on my own.
3. Should i cut short my stay?
Please help. Thank you.