I am mom to 3 sons, and grandmom to 3 grandchildren (2 girls and a boy). I don't know if I was really "ready" to have the first one, but I sure wanted him! I wanted to be a mom more than anything. I think it was my biggest motivation for getting married the first time. That is probably why it did not work (marriage not the child -- he worked out wonderfully!). But I did have a lot of learning along the way. Second time, I wanted another child and thought I was ready for him -- still had lots more learning to do!
Third time around, I wanted a child and was sure I was ready for him. Yep -- still a lot of learning to be done as they are all so very different. So, I don't know if anyone is ever completely ready to hae children. It just has to be a decision of what you want and what you are willing to learn and commit to doing over the longhaul.
It is just such a personal decision, no one can really give you advice on it. You will know if and when the time is right for you. No one else can tell that. If you decide not to have children, that is fine too. Although my children have given me more joy than I ever thought possible, and I know my life would not be complete without them, I do respect others' decision to not have children. We are all just as different as the children we may or may not have.
Desire to have them comes first -- then you get to start making preparations and asking the hard questions like when. I don't necessarily think you have to wait until you are financially wealthy, but I do think people need to be sure they can afford to provide necessities for them. My first two never had the latest & greatest, but they were well fed, clothed, and always had a decent roof over their heads. My 3rd was spoiled rotten, according to his older brothers.
But I don't think having the extra money was any big advantage for him in any of the important ways. His biggest advantage was time -- my husband & I both retired when he was young and had lots of quality time to spend with him. So, I do think that is a factor to consider. If you both work, how much time will you be able to spend with a child? How much is enough, is again one of those very personal questions. Some can make a few hours into serious quality time while some may always be around, but not really be spending the time on their children. You know what I mean.
So, I guess those would be the big 3 -- Do you WANT them, can you AFFORD them, and do you have TIME for them? Then you can start reading the books, forgetting what the books say and learning on the job!
It is the most important decision a person can really ever make -- to have a child is such a HUGE responsibility and committment. It is to your credit that you are really putting some serious thought into it. I think way too many enter into it lightly without ever realizing what it really means and what a huge undertaking raising a child is or should be. It is one of those investments that pays HUGE dividends though. They give back a thousand-fold in joy, laughter, and love!