Hi

You don't need to worry at all even if you are 21 years old you are still eligible for MBBS admission in AFMC.

This is because ,

As per the age limit to be eligible for AFMC for MBBS admission 2020 one must be at least must complete 17 years old by December 31, 2020 and must not be more than 24 years of age .

So , the maximum age limit is 24 years and you are 21 years old so you are still eligible for AFMC.

Also

if you aim to get into afmc, you need to target around  650 marks in neet.

For example,

In 2019 , 596 marks was required  for boys and 610 marks in neet was required for girls to get into AFMC

After qualifying neet cut off of AFMC , you will have to give some additional examination to get admission in AFMC , that is :-

*Test of English Language, Comprehension, Logic, and Reasoning which is called ToELR,

*Psychological Assessment Test i.e. PAT,

Interview

*After clearing these, finally you will have to go through your Medical Examination then finally you are selected for admission in AFMC.

For details go through

https://medicine.careers360.com/articles/afmc-mbbs

Thankyou