When calling an illegitimate child after his mother will cause harm

As-Salaamu Alaikum Ya noble Shaikh,
I have a question in regards to one of your answers. I have a first name followed by the first and last name of my father, unfortunately I was born out of wedlock. My mother wasn't muslim at this time 25 years ago, but has just become muslim this year(Al hamdu lillah). My question is would I still have to change my name to my mothers first name and family name even though when she did this sin she had never heard about Islam. Wouldn't this cause people to slander her and cause people to disrespect my mother and myself? Whatever is the right thing to do I submit to Allah Ta'ala. Please answer this question it is very important to me and my mother. May Allah bless you for teaching people the Deen you have helped me tremendously through your answers and kind words. JazakAllah Khair Wa Salaamu alaikum!