I completely agree with the other posters about getting counseling to come to the best decision for you and your son. An honest, open discussion with your boyfriend as to whether or not he'll be on board with an adoption is also extremely important and may impact your decision as well.
You said that you love your son more than anything and I believe that you do. The first step to motherhood is doing whatever is best for him. Sometimes, that does mean admitting that you may not be ready to parent.
I get the feeling that a lot of the other posters believe you should keep your son. And maybe you should. Only you can determine if your situation is the best for your baby.
A family member of mine got pregnant under less than ideal circumstances and chose to keep her child. Then, after the child was two, realized she wasn't going to be a good mother (and didn't want all the responsibilities that come along with being a parent). And then that little innocent girl was handed off to whatever family member or friend would keep her for any amount of time. By age six, she had seen things some adults would never want to see and been exposed to people she should never have been around. She had been shuffled around from place to place and didn't know who was good or bad. She's still in counseling and has very deep emotional wounds.
Will something like this happen to your son? I hope not. But, had my family member heeded the gut feeling she says she had while she was pregnant that she wasn't ready to be a mother, her child could have been adopted to people who were ready and willing to parent. Her daughter most likely would have avoided such a difficult and rocky start in life.
If you do decide to adopt, there are so many programs out there that let you choose the terms. If you want an open adoption, there are people willing to do that. The truth is that there are thousands and thousands of childless couples just waiting for a baby to call their own. If you do decide that now's not the time for you to be a mother, you will most likely get to choose the parents (with the help of a counselor, of course). Your child will be loved and cherished, not only by you, but also by two other people who know beyond a shadow of a doubt that they want to parent your child.
I guess the short answer to that long-winded response is that it's okay, very mature, very brave, and extremely loving to say, "I'm not ready to be a mother. I want my baby to have a mother that is."