It's understandable that you'd be a little jaded considering the divorce... I haven't been through that so it's different for me. And no, I don't think it's a bad idea to look down the road and have a plan in place for future sibs. I'd prefer my children to be full siblings as well so if you can do what it takes to make that happen I'd say go for it!
You've come a long way in the past few weeks! Sounds like you're in a better place and learning lots-Congrats!!