Ask HN: 8 years working, now 3-4 months off to learn. Looking for advice

I have a Bsc in Software development which was extremely practical and light to non existant on real math or algorithms. Since then I have done very well as a contractor programming mainly in java building webapps for your typical enterprise shops, banks, big energy providers etc.

Now at age 33 I'm considering taking 3-4 months after this contract to take the following 3 courses:

- http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-042j-mathematics-for-computer-science-fall-2010/Syllabus/

- http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-006-introduction-to-algorithms-fall-- 2011/Syllabus/

- http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-046j-design-and-analysis-of-algorithms-spring-2015/calendar/

I want to stop contracting and apply to a company solving real problems after this process, google, facebook, zalando, amazon, etc..

I have always felt terrified of the google interview process, or any test on a whiteboard for that matter.

In the 3 months, I plan to work 6-7 hours a day and get a tutor 3-4 times a week on chegg.com. If I have time left I would also like to work through cracking the coding interview.

Would love any feedback on this idea, i.e. if I'm missing the mark, or picking bad courses it's best to know now.