Class 11

Yes, as it is difficult to read NCERT thoroughly. Extra books give you reference.

Hi, Candidates who have passed class 12th examination from a recognised school/institute are eligible to register for Common Proficiency Test. Please find the link below for more details:
https://www.shiksha.com/college/the-institute-of-chartered-accountants-of-india-Delhi/exams/icai-exam.

The School Entrance Test conducted every year for Admission of students to class 6th, class 9th and class 11th in Central Hindu Boys School and Central Hindu Girls School, Varanasi. The School Entrance Test 2018 is scheduled to be held from 25 April -28 April at various exam centers. As per the official notification, CHS is going to activate the link of downloading CHS SET Admit Card 2018 on 11th April-2018. This year exam is over you may opt for next year.

You can take interior designing or fashion designing course after your class 11th and 12th commerce because, the stream does not matter to pursue any designing degree. Candidates must have an interest in and a flair for art and design. There is a number of designing colleges, from where you can pursue a degree in designing course. Here I am listing some best fashion designing colleges in India:
1. School Of Fashion Technology
2. Indian Institute of Art & Design (IIAD)
3. Vogue Institute of Fashion Technology
4. International Institute of Fashion Design (INIFD)
5. Arch Academy of Design
6. NID (National Institute of Design)

You can go for BBA at graduation level and MBA at Masters level as it doesn't include accountancy and related subjects.

Clear your basics. Prepare from NCERT textbooks. Make a timetable and follow it without any fail.

It depends on your location. So, make sure you go to the right person about the school.

Yes, you can. Just do apply the right time. Most of the good school start their admission process like form filling early like in January. Don't worry, just get admission in any school affiliated to CBSE and rest depends on your smart work. Be humble and be smart.
Good luck.

Hi Abdulla Jeelani,
You may continue your education from the same school, however, you can check the details here:
https://www.shiksha.com/aviation/flying-pilot-training/articles/career-in-commercial-flying-all-you-need-to-know-blogId-13472

You must have Physics, Mathematics as a basic subject with computer Science. And, you must also be good in operating the system, because it helps in you designing the aircrafts. Physics is the main and essential subject for the AE.