We did–After we agreed to get married, because we were quite sure, but at the same time we didn’t want to impose such a stark change right away in case the change would exceed one’s ability to cope with change which could lead to panic, meltdowns, etc. Neither of us handle change very well. We didn’t actually get married immediately of course. She packed up a pod and moved in next. It was months before.
We also talked about having kids right away. Not having them right away! But we talked about it immediately, I think like five minutes in, because isn’t it important to know?
As a counterpoint: nothing in life is without risk. I’ve seen friends take it slow and end up divorced, too.