B1 Superintensive course seems overwhelming to me as a passive and gradual language learner

I have been learning German since 2020 (Casually).Finished A1 in August 2020 and A2 in march 2021(i was not interested back then) therefore i never continued and just learned the language passively somedays cause i was busy with my Engineering classes and work .I wanna go to Germany this year for my Masters Degree so I just passed Goethe A2 with 86/100 with 2 months of preparation in October 2024 which was very easy for me. I just watched Easy German Videos and Duolingo everyday.

p.s- I wouldnt call myself A2 as my grammar is not that good

I have enrolled for B1 superintensive in Goethe which lasts 1.5 months. I am not used to learning 5 hours a day and im afraid that i will be overwhelmed with the load. What to do and when should i give the exam as i wanna arrive by March 2025 in Germany with atleast B1 level of German.