I'm an ex-manager who went back to being a developer. Here are some things I think you'll need to be comfortable with if you want to be a manager:
- Spending time in meetings. Everything from one-on-one meetings with your staff to meetings with higher management. The higher you get promoted, the more meetings you'll be expected to attend.
- Dealing with other company bureaucracy. One of your jobs as a manager is to shield your staff from bureaucracy so that they can get their work done.
- Not being an individual contributor anymore. Once you get promoted beyond being a lead developer, you'll be spending much less time on designing and writing code. You'll be judged based on the contribution of your entire team, not your own contribution. You'll need to start spending time mentoring your staff to make them more effective.
- Dealing with HR issues. You will be your staff's first point of contact when they want to ask for a raise or promotion, report problematic interactions with other staff, or ask for accommodations due to personal or health problems. You may need to fire some of your employees because their performance doesn't meet expectations. Even worse, you may need to lay off high-performing employees because the company wants to cut costs or cancel a project that they're working on. You may need to choose which of your staff get laid off. You'll need to be aware that certain actions you take could expose the company to legal liability.
- Because of the above, it will not be a good idea to be personal friends or drinking buddies with the people you now manage. For example, if the employee who socializes with you happens to be promoted while the one who doesn't gets laid off (even if the decisions were made completely fairly), it will be demoralizing to the rest of your staff and may result in your being accused of discrimination.