Evian I am going to be honest, brutal even but I don't mean to hurt or offend you. I speak from experience.
1. In 20 years time there are many things in your life that you will feel very differently about from what you feel now. Its hard to foresee what those things will be. One of them may well be having children.
2. In women, the desire for children is, to a greater or lesser extent, hormonal. Honestly.
3. In my opinion, having children should be what about what is going to be good for the children and not about what the prospective parents want. Can you afford materially and emotionally to be a single parent by choice? As I said in my first post, single parenthood happens and many many people make an excellent job of it but its never a good idea to do it by choice.