Kim, you've asked an honest question, and I'm going to give you an honest answer, unvarnished OK.
I don't think a single person should ever adopt an infant. I believe that it's best when children grow up with two parents. We need both a mom and a dad. There are so many couples lined up to adopt infants, there usually is no problem placing the infant in a home with a mom and a dad. For a single woman to adopt a healthy infant...I do believe that is selfish, always with the caveat that there are always special circumstances for some.
Having said that....
Steve and I adopted our kids from the foster care program. There are so many children in the foster care program who are shuttled from foster home to foster home with never a real home of their own. Some of these kids develop behavioral issues, some are sick, some simply don't get chosen for adoption. So, they stay in this foster care cycle, growing up without ever a true home and then, when they are 18, that's it. They are out, on their own. Period. Maybe they might be lucky and get a really good foster care family. But most who do foster care have to move on because the need is so great that for every child that gets moved out, several more are waiting to be placed.
I can't tell you how important it was for our kids, when we brought them home, to understand, to truly understand that they had a forever home. That we really were their mom and dad and we weren't going to make them go away if they were bad, or make them share a room with kids who show up in the middle of the night, then get to like the kids, just to have them leave and never return. Or they were the one who left and never returned. For my daughter, we were her 5th home in life and she was only 3 1/2 when she came to live with us. 5 homes in 3 1/2 years. Can you imagine what a little child goes through with that? And our son. Believe it or not he was considered "at risk" and "hard to place" because he was black and a boy. That's it. Being black and being a boy, this meant that, statisticaly speaking, he was unlikely to ever find a home. He's an intelligent, funny, good-looking, healthy child, but because of his sex and skin pigmentation, most didn't want him.
Anyone who adopts a child under these circumstances is doing a great good. Under these circumstances, the whole thing of "we need both a mom and a dad" takes second place to the fact that they don't have either or even a home to call their own. These are the "throw away" kids, the hard to place kids, the kids for whom a home of their very own is just a dream.
I'm not going to paint a pretty picture here: It's HARD work to undo the damage that prolonged foster care and multiple placements does to a child. Our daughter had severe attachment issues and it was just last week that she and I sat on the back porch and held each other and cried over her past. But, I thank God all the time that He closed my womb and brought her and my son into our home to be our kids.
So, pray over this and consider the issue from every angle, the pressures of single motherhood, the issues that children in foster care have, the fact that you will indeed need to figure out some kind of father figure for the kids (how do you get along with men in your family or do you go to a church with men that could be a mentor and father-figure for a child), the fact that undoing the damage that foster care did is emotionally draining and you won't have a husband to lean on. Prayerfully consider every angle.
And then, if you want to adopt an older child (over age 2) in the foster care system, I'll do every thing I can to help you through the process. Promise.