Hii Naresh... I must say there is no retirement age for a content writer. It's like a business where one could grow up to any level. But let me clear you, in India, the content writers have quite tough competition to grow and build their career. If you once enter this area, you will atleast need few years to be a good content writer. Minimum 2 years are required to write something very interesting and which can attract a lot of attention. Though sometimes, it gets hard when people don't understand the POV and a single bad rating can destroy careers. I want to say that till you write good and something which attracts a lot of people, you don't need to look behind what you have done till now. Your growth rate will be exponential and will achieve high career. On the contrast, if it's not so appealing then you might need to find a good career!!

So there is no particular retirement age of a content writer till his writings get attention.