As per your statement your penile size is 1" in normal condition and 4.5" when erect.
To satisfy a lady and to have a child birth, the size of the penis does not play a major role.
You must understand what is sex and technique behind it. For any male the glans penis
is most sensitive area, like that females are also having most sensitive area. Understand that it is not inside the vagina. so the size does not count. only the erection and how you perform it effectively is important. more over 4.5" is 100% OK. Don't get depressed by watching BFs.