It takes on default 60 weeks after birth for a baby to grow into a 17yo slave-girl (appears in your dungeon, with an appropriate 'your daughter' trait, if that's the case, males are sold automatically). You can change that quite easily in the config file to however many weeks you'd like. It does notify you when a child grows up for both male and female children maturing. It should show up as a red notification at the top of the summary list for that girl.
It would be, but unless you know how to code, don't count on it lol. You don't see how many weeks they have to grow, but some UI mods add a column in the girl management screen that lists how many weeks a girl has before birth.