Birth certificate

Two questions: My birth certificate is from 1998 and while there is no damage or modifications done to it, it has been folded so many times, the creases are fraying at some of the edges, is it okay to use? Also, my biological dad was not present at my birth and his middle name is not on my birth certificate but he does have one. I am applying for a new passport altogether because mine is more than 5 years expired, I was a minor when issued, and I changed my last name from my maiden name to a different last name and back to my maiden name. Should I include his middle name in my application or not? I don’t want conflicting information and cause delay because I have a trip planned for end of July-August. Thank you!