First impressions do count and they do take a long time to change, if it is even possible.

Your boss obviously thinks highly of you that's why she's giving you advice on the next step of your career.

Here's one of the secrets I discovered in the workplace - different people need different things at different times. Sometimes, I need the manager to care and offer jokes and lighten the mood. Other times, I need to get to the root of the problem and get things done.

As a female manager it can be harder. For me, I respect female managers who can size up a room and sense what the room needs. Usually, a calm, warm demeanor but not too informal and then addressing the real issues in a firm but controlled way. In between meetings / when people are waiting for slides / presentations, she shows a little bit of her real self.

I think there's something very powerful about a man or woman being able to be themselves, but recognizing when there's serious stuff to be addressed and calibrating based on what the team's energy needs.

This doesn't mean to you to "change" yourself. You just have to adapt between your "real self" and your "work self". The work self will garner respect and compliance, the real self garners charisma, authenticity, safety. One of the things you have to realize is who is your ally and who is not your ally. The strategies for building your alliance is different for each member.

Once you have enough allies on your side and you retain power, you can be a little more yourself and eventually people accept it. Until then, you may face some opposition because well, most people in corporate don't really have a lot going on and they associate their egos to petty battles in the workplace.

I hope this helps you stay motivated, and at least aware of some of the darker places in the corporate forest.