Yes, you have to age it manually or with aging points, or you buy an Artemis Arrow at the Black Market for one pass, which makes gestation half as long. I have an account on Howrse.com too :)
Foals should NOT be weaned before they are 3 months old. Six months is better for the foal.
I prefer gradually weaning over a few weeks as they approach 6 months rather than an abrupt separation.