Hi Amlee and Welcome to the forums! What an emotional time this is for you, I have been there, 16 years ago I placed my first born son for adoption. It sounds like you are almost definite that you arent ready to parent, but please weigh all of your options and rememebr that being a mommy doesnt mean you still cant obtain your goals in life, it may be a little harder but If you want to do it there are lots of resources for you to do so!
If you do decide to go the adoption route, please do lots of research on your options there as well, there are semi open adoptions, where you can receive pics and letters of your child periodically, Open adoption, where you may have more contact, periodic visits even, closed adoption, where you still may chose your childs parents and give the info your child will need in the future for medical info or whatever....so as you see there are many things to consider. Also may I suggest unbiased counseling outside of the agency you may chose to use, you need some looking out for you and your child with no ulterior motives
Please feel free to contact me via Pm if I can be of help in anyway.
Good Luck!