Raj, NEET is also conducted in Hindi. If you opt for Hindi as the medium of your Examination, you will get Question paper in Hindi. Along with that, questions will also be asked in English. So it is not necessary that you have to prepare in English for NEET. You can prepare for NEET in Hindi and also write the exam in Hindi. But once you get a seat and move to a Medical College, the medium of Instruction is going to be in English and so you have to learn English from now so that you don't find it difficult later when you join a Medical College.