Hey Shivani,

For admissions in Delhi University the age limit is not necessary. It is fine if you are below 18 or above that, you can still get your admission done. 

Also, you can attach your EWS certificate  and not your father's as it will not accept it. If you don't have one then you can not get admission in that category and you have to go for admission under general category. You can also, contact Delhi University's help desk and ask them fo the same if they can do something in this situation.