Is there any age fixed for career planning?

The answer of this questions is -NO.
Whenever you feel that you are sailing into a wrong boat, try to change it. As a faculty in a MBA institute , I have experienced that many veteran professional are turning to acquire more knowledge and skills.
Career planning can be done at any stage or any age. The thing is - You have to mature enough to do your SWOT ( Strength , Weakness, Opportunity and Threats ). When you will do your SWOT, do it with a open heart and limitations.
Then decide , you are in a right boat or you need to change it. Make some SMART Goals ( Specific , Measurable , Achievable , realstic and Time bound ) Goals and analyse them and see the changes within you.