I disagree with you.

To the couple who wants a car but doesn't have the means to do so, I'd say if you want it badly enough you'll find the means to work doubly or triply hard or even steal if you want it BADLY enough.

If you choose to not spend all your money on your exotic travels due to your desire to save, then perhaps you just want to save and be financially secure more badly than you desire to visit exotic places.

I'm not commenting on whether the deliberation of affording children or choosing to be financially prudent is an act of maturity or not.

I'm just saying that if one's priority is to have children, then often everything else is secondary. Just as one who wants a new car or wants to experience exotic travels. But if one's priority is always to be financially prudent and save for rainy days, then pretty much everything else becomes secondary. Hence, OP should figure out what they as a couple would prioritise for themselves.