I have only made the stirred curd with goat milk, but I have found that aging it 3 months isn't long enough, not enough cheddar flavor. 10 months was too long, added bitterness. But 6 months was just right, for a medium sharp cheddar. I have to add that I use vacuum seal bags placed in a fridge, and don't let it age naturally in a cave. Aging naturally, or binding in cloth would probably let you age it much longer for a very sharp cheddar. The key for me seems to be making sure to hit the pH targets, and cutting the slabs smaller if I see any whey puddling in between flips.