Exam

Right now you are in 11th standard. And in any case it's not required to prepare for CAT at this stage. Maximum 1 year is more then enough for CAT preparation. But for your better future, it's very important to get good marks in 10th and 12th boards
Only then you will get the best college for your graduation. Try to get atleast 90% marks in 12th boards so as to get the best college. And you can start preparing for CAT in the 2nd year of graduation if you are really very serious about it.

The National Eligibility Entrance Test NEET formerly the All India Pre-Medical Test (AIPMT), is the qualifying test for MBBS and BDS programmes in Indian medical and dental colleges. The examination, which offers 90,000 seats in MBBS and BDS Colleges of India, is conducted in the month of May every year. All the best!

Yes. You can if you have knowledge of that field but it's completely up to you. If you think you have enough knowledge and interest in that field you can definitely change. I know one of my classmates who change their field from Science to commerce as he doesn't understand Science and teachers also suggest he change and he passed 12th with a very good grade.

There are 5-10 paid seats in FMS BHU (category-wise). Please visit the FMS BHU website for more information.

Yes, if you are a Diploma student and want to take direct admission in Maharashtra state engineering colleges then it is mandatory to give the leet exam.

GATE-XL stands for life Science and GATE-XE stands for engineering Science, you can take any one of these according to your background subjects if it is related to mathematics you can go for XE and if it is related to biology/agriculture you can go for XL.

You have to take the rank below 5000 in a general category, to take admission into JNTU.