We are working on to develop a PMO Objective for the upcoming year. We plan to strategise the objective based on the needs of the organisation. To kick-start, we are doing an assessment on PM Maturity scorecard to see where we stand. As it completely new to us, any insight on how to do it will help us a lot.
There are quite a few commercial and freely available frameworks for assessing project management capability so don't reinvent the wheel. I would recommend starting with an understanding of where you currently are - what are the costs your company is paying for being at your current level of PM maturity and what are the vital few, low hanging pain points to tackle? If you understand that, it will make it easier to define good targets for improvement.