Congratulations. I had my first at 46 with a much younger wife as well. The first 6 months will be miserable with the pooping, crying, and puking. Little sleep for anyone in the house. I started with a jogging stroller around the 6 month mark, walking at first and then graduating into jogging. She was in a bicycle trailer at the 12m mark using a 5 point harness and helmet. We never went out of the neighborhood as I was scared of the heavier traffic outside the hood. My daughter just turned 5 and other than the fist 6 months it has been a glorious ride. You should feel very lucky that you didn't miss out on the experience. Daddy/Daughter relationship is wonderful.