Answer

Hello,
As a rule, today there is a very stringent approach among halakhic decisors regarding procreation. It seems to me that this is a hysterical reaction to the Holocaust. Delaying procreation mainly involves an issue of alacritous people performing commandments early, and if in the end one does not succeed, then there is a concern of neglecting a positive commandment under the rule of “prevented by circumstances on the last day.” As for which contraceptive method, that has to be clarified separately.
In any case, there is definitely room to be lenient if you truly see this as very important. But even so, it is worth taking the following into account:
1. There is a chance that when you try, it will not go so quickly, and perhaps you will not have as many children as you want, and then you will regret having waited. There is also tension until children are born, and there is an advantage to easing that as early as possible.
2. Your relationship itself is partly based on the children (as Rashi says on “and they shall become one flesh”). And even if you try immediately, you have about a year to build your relationship before the child is born.
3. The waiting itself can actually harm the relationship, because it creates a feeling that you are testing your relationship to see whether it is good, and only then will you decide to have children. But that itself may create a situation of a temporary relationship that is constantly being tested, and that may be unhealthy for your relationship. By contrast, if you jump straight into the water, you convey confidence in your relationship, and that itself strengthens it.
All the best and success,