Is this wrong, having my boyfriend knock me up because I want another baby b4 i'm 30?

I have 2 biological children and I would like to have another baby. I am separated from my husband and do not want him to father the child. I have to blonde blue eyes children and decided that I want a brown eyed kid. My boyfriend is tall, brown hair, brown eyes, nice bone structure, and intelligent but not ready for kids (he's 9 years younger then me) I asked him if he would get me pregnant and I would raise the child alone unless he wanted to visit with the child at times. He agreed and we've been having unprotected sex for 2 weeks. Last night my very troubled stepdaughter found out that I was trying for another baby and she pretty much freaked out. I know it's hard on her, her mother is dead and her father moved out, she lives with me until the end of the school year. She told me I was immoral and that what I was doing is "Wrong" what do you think? I do not think what i'm doing is wrong, i'm having a baby i'm a grown woman with a good job, I have money saved, I have health insurance, I own a condo, and I drive a nice car. I'm also a damn good mother who has to exceptionally brilliant children that are adjusted and loved. Why is it wrong that i'm having a child?