Yeah generaly most people on our planet won't think about milf been below 35-40. Thou some of 40+ ones can fall under additional type of women.
Well, when tried IMVU for the first time I was treated like "mamacita" (mommy in spanish) and I was around 20...
Having been around in the 80's* when MILF became a genre, it was in references to fantasies about your friends' or peers' mothers. People known to you are XXXX's mum or Mrs YYYYY (it was the 80's they were always married). So with the requirement for your and hence your peer-group to have hit puberty and a general desire to avoid harrowing backstories that would give a 35-45 age range
Where as if you are someone who hangs round kindergarten gates in just a creepy but not criminal way, your target group being mothers of young children so women in their twenties. They are generally referred to as "Yummy Mummies" [YM] ( particularly if they were former members of a Girl Group )**
* being around in the 80's means that age appropriate relationships are starting to slip into GILF territory (strangely the only non-gendered one of these acronyms [maybe everyone thinks your past caring?])
** DILF does exist in a similar age range with it's straight equivalent of Sugar Daddy (ladies please No!), but I am just not aware of the male equivalent of YM regardless of orientation . However I suspect that if your were to conduct a practical exploration of the subject you would rapidly be labelled "Home wrecker"
Exactly.