You are eligible to apply for a Student visa to study in the United Kingdom if you are 16 or over and you:
Application
If you are applying from outside of the UK, the earliest you can apply for a student visa is 6 months before your course starts. A decision will usually 3 weeks.
If you are applying from inside the UK, the earliest you can apply is 3 months before your course starts. You must apply before your current visa expires and your new course must begin within 28 days of your current visa expiring. A decision will usually take 8 weeks.
The cost of a student visa varies depending on whether you are applying from inside or outside the UK:
In addition, you will have to pay for a healthcare surcharge as part of your application.