I would leave the old leaf in place. It will eventually die away. While it's there, it's providing food for the baby plant. Usually, the mother leaf dies off and can be pulled away by the time it's no longer needed by the baby plant.

It's doubtful that, if it were removed and replanted, it would grow another plant. It's already used up a lot of energy growing the first one.

Thank you Brandon, that does make sense. I'm just surprised that the "mother" leaf is still there and looking great. I started rooting it 4 or 5 months ago and have quite an established baby Echeveria going.

It's making me want to do many more with my other succulents.

Be careful SproutingLexi, the addiction can be very troublesome. Eventually you get like me (I mean those people on that show Hoarders) and have so many plants that you can't see out of your windows.