Now I'm going to keep it 100% real on this one (as usual).
Your body is screaming I'm ready, but wisdom whispers your not. Your biological clock may feel that your body is ready to produce a child but you have to think about the consequences of every action and inaction.
When you follow your unconscious mind, body, or heart, then it's usually the right way to go- meaning it's probably fate. And the world will change around you for your circumstance. "Jump and a net will appear".
But you already talked to your spouse about it an he has voiced his opinions to you about the matter. Trust him. Trust the man that you married. If he says that 'we're' not ready(meaning you+him), then he means that his half is not ready. And the reason probably being because he wants to be completely stable in life so that he can give the child everything he/she needs. That's not being selfish, it's being wise because it takes more than just a loving home and finances to cover the essentials of parenting and produce & rear a well-balanced child.
There is a tremendous responsibility with becoming a parent- especially a mother. Mothers have greater influence on the child, especially in the early stages of his/her life when guidance is critical.
All-in-all..... Preparation is needed.
"The Mother's Preparation Strangely Neglected. The child's first teacher is the mother. During the period of greatest susceptibility and most rapid development his education is to a degree in her hands. To her first is given opportunity to mold the character for good or evil. She should understand the value of her opportunity, and above every other teacher, should be qualified to use it to the best account. Yet there is no other to whose training so little thought is given. The one whose influence is the one for whose assistance there is the least systematic effort."---(from Child Guidance)
I strongly recommend that you read this book. It helps guide us as parents to lay down the foundation for child rearing.
And. P.S. I had my first &only child at 18 and I am now 20. Sure I am financially stable but things can always be better. Her father and I are good parents and have that old school demeanor, but alot of times we are very busy don't have the time that we would like to truly guide and appreciate her the way that children are meant to be.