Ye, I'm just holding my toung reading a lot of what is being said. A lot of people will tell you exactly how to raise your kids. We did co-sleep with breast feeding and it worked well for us.
People go on about routine but I found that if you force the routine too much then you are stuck with it and almost imprisoned. Means that if you ever have to break it then the world ends. People who know us say that our kids is so relaxed and flexible but it could also just be how she is.
Kids will tell you when they are hungry and tired, you just need to learn how to listen for that.
Ye what works for each family is totally different. Whether you co-sleep until 18 months or have them in their own room from 2 weeks, it is just about paying attention to the baby really. I will give an example of how we "messed up" with our son and sleep. We learned from the experience and will not make the same mistake with baby no.2.
We would always feed our son a bottle before bed. Then when it was finished he would go in his crib. Sometimes he would fall asleep on us, sometimes not. But he always managed to fall asleep quite comfortably without us in the room if he was still awake.
Then one day he started getting very frustrated with being held and being given the bottle. He pointed at his bed and wanted to go straight in. The mistake that we made was in giving him his bottle to hold in bed himself.
It seemed harmless at the time. But after a while, and a few mild colds/chicken pox infections, he started waking up more frequently at night and always screaming out for a bottle to get him to go back to sleep. He went from waking up once at night for a change and feed, to waking up 2 to 4 times.
We finally got rid of the bottles just after 2yrs old. It was a bit of a struggle, but since then he sleeps through 5 out of 7 nights in a week. Because his wake ups were not for fluid or nourishment, but for assisting him in falling back asleep. We enabled that behaviour which prevented him from trying to find a more balanced night time sleeping pattern. That was not his fault but ours.
In retrospect, we should have attempted to remove the bottles that first night that he showed frustration at being held and fed before bed. It was possibly a sign of being ready to try to sleep on his own and not wanting the bottle.
So in short. If your baby is sleeping through earlier than 6 months, you might be doing one or two things right, but mostly it is the type of baby that you got (Imagine a 90%/10% ratio in favour of the baby). As they age past 6 months, the scale slides more and more into the "parent's fault" side of things. Some of those things are unavoidable, but I think it is worth having a good think about your child's sleeping habits and recognise any bad habits that you may be enabling or promoting.
As far as the OP is concerned though, that is a long way away. Just roll with the punches for now, it is a tough enough job as it is.