Hi Meet,

First of all your admit card is released, this means your application wasn't rejected. I stated this because in entrance examination if any of the documents do not justify the specifications the candidate is notified about it and is asked to correct the document during the correction window is open. If still the document doesnt meet the specification the application is cancelled.

If you have recieved your admit card you can surely give the exam and you need not worry about the signature size as far as the signature is clearly seen even in the small size.

Secondly now you can do nothing about the signature as your admit card is already released.

If you still have doubts about the signature i request you to send an email or contact the authorities over a phone call.

Hope that helps you