Dhampirs and non-human mortal parents, starting ages, and ignoring starting age

[Oxylepy]

So, one of my players wanted to be a Dhampir but wanted his mortal parent to be a drow, which has the same starting age as a dhampir. I ruled that the dhampir's starting age would, similar to a human, be much greater than that of the drow parent as they are being haltes developmentally by the near immortal blood of their undead parent, and not by some innate dhampir overarching development.

Further I pulled up the Book of Erotic Fantasy to read the passage for Half-Elves and how the aging system would alter him psychologically due to the culture he was raised in (possibly the only book I know of to cover a relatively vital character aspect for older race hybrids). Then I offered that he could start at a much younger age, he'd just not be sexually inclined due to the pre-pubescent mentality of one not pushed by their hormones.

He ultimately decided to go human as the game shifted further from the underdark, and he wanted to play the character at its full sexual development, losing his mortal parent in the process.

My inquiry remains, though, should Dhampirs be older than their mortal parent, and can one choose earlier starting ages for non-human characters which are rightly physically developed yet not mentally?

[Weirdo]

There's a lot of personal preference in play here.

I like dhampir with human parents to age more like half-elves - they take only slightly longer to mature, with most of their lifespan added in maturity. If human dhampir took 110 years to reach adulthood, the vast majority would die in childhood. (This issue resulted in an adjustment of tiefling and aasimar ages match their parent races, but I don't think anyone revisited the dhampir at that point.)

If I were going to be more general about it, I'd probably say something like "they reach adulthood at 110% the age of their mortal parent race, middle age at 125% the age of their mortal parent, old age at 150% the age of their mortal parent, and venerable age and death of old age at twice the age of their mortal parent."

PF really doesn't separate physical and mental development, but I think it might be interesting to do so as a worldbuilding exercise. For example, elves in my current setting have a long adolescence from about 60-110 in which they are physically mature but emotionally immature. A player could decide to play an elf in this range if they thought they could handle the roleplaying well, in the same way that we previously had a 17 year old half-elf in one party who was technically an adult by her human culture's standards but was mentally more 14-15 years old.