How/Where do i begin?

Have an unusual situation...... My fiancee and I have been together for 6yrs and because i had a tubal after my last son was born (he's 9) we cant get pregnant right now and have talked about adopting..It would seem alot more sensible to adopt a child rather than having the surgery to reverse my tubal. I know this young girl here that is pregnant and wants us to adopt her baby, problem is that I dont think we would "pass" the requirements for adoption right now. I mean we arent rich or even married yet, we can provide for a child both financially, physically and emotionally. But dont have the "records" to prove it..We're lower middle class.No criminal records. We've discussed our options and i just dont want to pass up this opportunity and neither does he...Can we take guardianship of the baby and possibly adopt in a couple of years w/out any penalties, if the bmom and bfather sign rights over to us or do we have to follow the standard steps, How can I not lose this opportunity???? Someone help!!!!