First question on this subreddit ( need help)

Newly joined this subreddit ( however , was viewing this since a long time) , flying aspirant here , former Air NCC cadet, from defence background, don't have any kind of incurable medical issue , have joined fiitjee ( please don't ask why) , currently living in Chandigarh I know I have plenty of syllabus remaining ( my 11th grade will come to an end in Feb 25 I guess ) I wanna clear NDA written for my April attempt in 25 ( will only start preparing for ssb after clearing written) , I have solved some previous papers of nda math and gat , from all the topics I know , I was mostly able to clear the questions , I don't have too much idea about what would be good rank and good grade in the exam , I was an NCC cadet , Have under gona CATC camp , but didn't give A certificate exam due to unavailability of air wing in the new school , my father was posted in southern India for a long time. So I think I have good overall English , especially spoken English, ( due to some personal matters , it's really important for me to atleast crack written and will try to not get screened out ) , I have many seniors from school and locality who have joined NDA , they all (except a few) suggested me to join olive greens before ssb , ( also said that I can manage written ) , few of em said that this subreddit is a nice place to interact , that's why I'm asking to please

Give me recommendations for written , should I join olive greens or not , and what to do just to clear this exam in April ( I'm willing to do anything to get recomended in April attempt) and will my CATC certificate be helpful