The right time to apply for a UK Student visa depends on several factors, such as the start date of your course, the processing time of the visa application, and the availability of appointment slots at the visa application center. Generally, you can apply for a UK Student visa up to 6 months before the start date of your course. However, you should not apply too far in advance as your visa may expire before you are ready to travel to the UK. It's also important to consider the processing time of the visa application, which can vary depending on the country where you are applying from. You can check the current processing times on the UK government website. In addition, you should book an appointment at the visa application center as early as possible, as appointment slots can fill up quickly during peak periods. Overall, it's recommended that you start the visa application process well in advance of your planned travel date to the UK, to allow for any unforeseen delays or issues that may arise during the process.