This is a difficult question to answer as much depends on your own level of experience and confidence. However, please remember that a lot of forward planning is needed.

Depending on the time of year, the earliest available dates to take the CSA can be longer than 2 months after your application. In addition, it can take 6-8 weeks to get the result. If you fail, this means going through this cycle again. This can be a huge problem if you have to meet dealines for residency applications etc.

If you have clinical experience and feel confident, then you should take the CSA as soon as possible. An extremely important point to remember is that the step 2 score is vital for your residency application. Your step 2 preparation should not be diluted by CSA preparation at the same time!!