Hello Ruchi, Candidate want to apply NEET 2020, lower age limit is 17 years.  Candidate must be at least 17 years old on 31 St December.  But as you mentioned in your question, That you are in 11 th class,  You are not eligible in education criteria.  Because candidate must have to complete 12 th. Or 12 th appearing students can also apply.
I hope it will help you.
Thanks.