Hello Susanta,

Here we go with all the criterias. Check link given below..

https://medicine.careers360.com/articles/neet-eligibility-criteria

Here it is written that maximum age criteria is 25 years for unreserved category and no fixation are given on maximum number of attempts.

Don't get confused by anything and just check the link provided above.

It'll help you to know that you are  allowed to give any number of attempts until the age of 25 yrs.