I think that, while you have to be “ready” to accept children lovingly as soon as you begin having sex (as soon as you are married), you aren’t required to begin actively trying to conceive on your wedding night. I’m not a theologian, so grains of salt all around, but that’s the way I understand it.
My husband and I began having sex on our wedding night and used NFP, in which I had–at that time–very little faith. I didn’t think having children was something we’d have to try to do. But, just in case it did work, I figured we’d have to at some point at least open it up to chance. So we agreed, either when we were engaged or newly married (I don’t remember which), that on our third anniversary we would have sex, no matter what the chart said. Obvious with 3 years to go, there was no predicting if that would be a fertile date or not. And we weren’t ruling out that we might be ready to “try” before that, or that a baby might happen in the first 3 years of marriage without trying. We just wanted some point at which, if we hadn’t already begun a family, that we opened up to it a little more generously, without regard to our financial situation at the time.
Not everyone has stability just because they happen to be married, nor do (I think) you have to hold off on getting married until you have a stable income and place to live. My husband and I moved 4 times in the first 3 years we were married, and we were far from our families. We began our marriage with no savings and one job between us, in a housing market where even when we were both working we couldn’t find any way to get out from the black hole of renting. We got married not because we had a lot to offer a child at the moment, but because we were sure that we’d found the person we’d be raising children with. And because, as my mother says, it was getting to be the only decent thing to do. We’d been dating for 4 years, and we were ready to make love, move in together, and become a family. It would have been OK to have a baby right away. But we weren’t ready to actively try to conceive.
For the record, NFP did work, and I’ll admit I was starting to get disappointed by the time our 3rd anniversary was in sight. The month of our anniversary, we were pretty lazy about collecting data and lax in rule application (see, it was working soooo well be got cocky about it). Of course I knew by then that our anniversary would not be a fertile date–in fact, I’d probably have my period. Disappointing. Except I didn’t have my period that day, and when I still didn’t have it the next morning, I realised I was officially late. I took a test and found out I was pregnant. Our choice of 3rd anniversary was arbitrary, and the pregnancy was accidental, but they lined up anyway. It was the right time.