Not to worry, If you didn’t studied anything, You can start from today, but must start it. Don’t take it lightly or you are the one going to lose. If you are really serious about NEET and want to crack it. You have to show some dedication, if you study seriously you will make it.
You asked for how to start, So, I prefer you should clear your basics first and complete the syllabus as soon as possible, As you already know, there is a time lacking for you. Secondly, you need to revise your concepts several times.
You should start from Biology, as its the most easiest subject rather than Physics and Chemistry. Biology is also a most liked subject. Read NCERT number of times, Prepare notes for revision and must go thoroughly with all the diagrams, practice them. After Biology, Don’t forget other two subjects. You have to go thoroughly with those two subjects also.
Always Remember, Don’t ever look down on yourself and don’t ever compare to others, that you are lagging behind or so, these things just going to demotivate you. Always be positive and practice as much as possible.
Do both hard work and smart work together.
Good Luck.