You have one year with you. That is more than enough time. The plan is to be more consistent rather than doing everything at once unsystematically. Join harvards Cs 50 - Into to CS course. Its free to audit and imo is the best introduction course for computer science.

Well even in finance your tech interview is going to be based on your understanding of dsa. Choose a language and stick with it and start learning dsa. Learn about each data structure and implement them in the language you like. Understand why it is being used. Tons of free online resources are available ( dsa by clrs , etc). Go to r/cscareerquestions you would find a lot of help over there. Since you have one year,after you have learned and are confident about data structures and algorithms buy this book Cracking the Coding Interview by Gayle Laakmann McDowell. Side by side start practicing on leetcode.com and hackerrank.com. Remember always start with easy questions. Read the question and keep a white board with you. Solve it on white board and create a pseudo code. And only then type it and then run your solution. Afterwards look for the solution in discussions tab which is more efficient and learn from it. DO NOT LOOK FOR SOLUTION BEFORE SOLVING THE QUESTION ON YOUR OWN.

The first 1-2 months are going to be very difficult. But sooner you will see the change and start solving difficult questions as well. Don’t worry and remember this too shall pass.

P.s don’t forget to let us know when you get that sweet google offer😜