Aoe II -vs- Aoe II HD question

I remember in the original game, playing standard games the enemy wouldn't age up until after you age'd up first. Now that doesn't seem to be the case anymore, so I cannot control the pace of aging up. I miss this option, does anyone know what the difference is and if there's a way to go back? I can't play the original AOE II because my new computer won't play old CD stuff, so I'm forced to play the Steam version which is what I have now.