How do I push my old coworkers now that I'm their boss?

Yesterday you stood beside them. Today you have to push them toward targets you know land hard on their lives. That shift is genuinely painful, because you have not forgotten what the floor feels like. That memory is not a weakness. It is what could make you a good boss. You cannot pretend the targets away, and pretending you are still just one of the crew would not be honest either. What you can do is carry the role without losing the humanity. Push for the numbers and see the people at the same time. Those two things are not enemies. The next time you have to ask a lot of them, say the hard part out loud: that you know it is heavy, and you have not forgotten. Then do one real thing to make it lighter where you can. You do not have to choose between being fair and being kind. The best leaders your crew ever had were both.