You need to be 17 years atleast by December 31st of the year of admission. So, if you want to appear for NEET 2020,  you should be 17 years atleast by December 31st, 2020. You will be 17 years and 2 months by December 31st, 2020 and so you are eligible for NEET. Use the link: https://ntaneet.nic.in/Ntaneet/Registration/NewReg.aspx . You can check the complete application process at our page, https://medicine.careers360.com/articles/neet-application-form.

Yes, you are eligible to write NEET exam in 2020. According to the criteria mentioned by NTA, all the students whose DOB is on or before Dec 31, 2003 are eligible to write NEET 2020 exam.

So, be happy, you are eligible to write the exam this year.

For further clarifications, kindly let me know through comment section.