Does the parents' age matter in the quality of a child's upbringing?

It does, but it shouldn't. The older you are, the more life experience you probably have (but that doesn't mean you're mature and it doesn't mean you should have a kid). Some young people are fantastic parents, some older people are awful parents. It really depends on the person, their own upbringing, and the experiences they've had during their life (however long that has been thus far). I personally think the older the better as it will give one more time to create a stable environment (financially, emotionally, etc.) but every home and family is different and beatuiful.