Have I committed a crime by having only one child?

my daughter is 6 years old now and whenever people ask me when i am going to have another one, I say that we have decided to stop with one, they are like thrown into a surprise “No way, really or are you kidding or I’m sure you’ll change your mind soon?!”, nearly 9 out of 10 people i speak to have asked me such questions. when it comes to my relatives and parents and mainly my grandparents, i am given a long lecture about how we need another grand/great-grandchild or how crazy we are to not have another one, that we are committing a sin by letting this child grow alone and that she will grown into a selfish one and not mingle with other kids and life will be ruined and all sorts of things i even asked my daughter some time recently if she wanted a brother or sister and how does she feel about it, she said just this, "Not at all, me, you and dad are enough for our family.” and at that moment, I had no doubts that we had taken the right decision do you think having an only child will effect her life in any way?