Canada

Children cost approximately $15,000 a year up to the age of 18.

Keep in mind this figure includes things like cost of shelter. It certainly costs money to shelter a child, so the $15,000 isn't invalid, but not applicable if you are going to account for shelter elsewhere. Double entry accounting doesn't mean accounting for the same thing twice.

Somewhere closer to $4,000 per year is what is generally accepted as the cost of the child alone, excluding such externalities which are a real cost, but reasonably accounted for elsewhere. This brings you back into the black with some money to spare.

Note, even the $4,000 (average yearly cost over 18 years) includes childcare costs. This means the typical parental unit should be able to double its income expectations from what you have presented. If one parent is foregoing an income to care for the child, then $4,000 would be reduced.

Oh shit, we’re in the red now with -$1,904.70

According to Statscan, the average woman is 29 years old when she has her first child. For the sake of discussion, we will assume the partner is of the same age.

Employment regulation varies by province, but generally one is expected to start working at the age of 14 and somewhere around 20 hours per week. There is a legal expectation of being under the care of an adult for those first four working years, which means it is, for all intents and purposes, pure profit.

If we assume a youngster is paid $10 per hour, that is $7,500 after tax each year. If we assume a 3% interest rate, that leaves one with around $50,000 in hand by the time they have their first child even if no further saving takes place after turning 18. But it takes two to tango, as they say, so actually a combined $100,000 is available.

Even if your family really is haemorrhaging $2,000 per year once you turn 29, you still have 50-some-odd years of runway. You could quite possibly have great grandchildren by the time you run out of money at that burn rate.

pay down debt

There is capital benefit to housing and automobiles, so debt may be justifiable there, but you have already included those payments in your earlier figures. What other debt could there possibly be? The average Canadian isn't starting a business and your cashflow figures are positive before the child comes along. No need to account for the same thing twice.