Neet is purely based on the syllabus of class 11 and 12th topics so you need to master them in order to qualify NEET with flying colors and get admission in top colleges. I would suggest you to make a schedule plan and try to cover the topics of class 11th along with studying for class 12th , devote a week 60% to revise class 12th topics and 40% for 11th this way by Nov or Dec you'll have your revision done completely and after that you can solve previous year question papers to test your knowledge and also learn time management as it plays an important role in competitive exams.
Hope it helps.
Thank you.