Why do my girls need to grow up so fast so my 11 year old had a busy day

First i get a call she wants to join band instead or play Villon . I mean a text . then i get a call she lost a tooth and the tooth fairy needs to come . but my oldest which was with me get a text or many text about what happen to her today . She got her period . Oh no am so not ready . Why do little girls can not be little girls .. she handling it well but it always makes me sad . I wish this did not happen to girls until they are least 15 or 16 . 30 be good . lol
So my younger one remember 10 months only younger say see mom and me are the only one with out it , lol see i don't get one as i take a shot for my head aches Depo so i don't get one and no more head aches . I just want them to be kids .. I was hoping i had another 6 months or years for that matter until this day came . Always mades me sad .

How to teach my teen to grow up ..

I think that what i want to do . He did not do great this semester at college . and he work while home and blow his money well my words lol . instead of saving some while he short my thoughts . I just don't know how to help , teach or show him how to grow up . I feel he still wants to act like a 16 year old and now almost 20 year old .
He a great kid , kind , loving , no drugs . so what to do ?
Just a little sad , little frustrated and just lost ...