Congrats, Eddie! On everything.
I think you got some good advice here, but you need to discuss all this with HER. I think you've made it very clear that you want to do the right thing by her, you want to do the right thing by the baby, you want to protect them more than anything else. Lay it all out there, tell her how much you love her, and the two of you decide what makes you all feel "right". And either decision (marriage or not) is completely defensible if that is what you both decide.
I also think prenups are a great idea for anyone who's accumulated anything in life before marriage or has any kind of complications. It's like having insurance--you hope you will never need it, but it protects everybody if the worst happens.
Hugs--I'll let someone else catch the bouquet when the time comes.
