As per the latest eligibility criteria of CDS 2020, the candidates between 20 to 24 years are eligible to give this exam.
You are 23 now and you are going to be of 24 years on 4 May 2020 so you are eligible for the respective exam in each and every course ranging from IMA to OTA.
You have total 1 attempt remaining.
Feel free to ask doubts in the Comment Section.
You may refer to this article for more information about CDS 2020 Eligibility criteria.
I hope this information helps you.