Hii

For NEET UG, the basic eligibility is that you must have qualified class 12th examination with subjects physics, chemitry and biology/ biotechnology with atleast 50% aggregate marks. Also you must be minimum 17 years of age as on 31st december of the particular year of admission.
So since you have the aggregate as 50% in PCB, yes you are eligible for NEET.
The application forms have already been closed, hope you have filled the form. If you haven't been able to fill the form this year, you will have to wait till the next year to appear in NEET 2020 then.

Hope this helps
All The Best!

Yes you are eligible.