carrer doubt

It is a difficult decision for sure. You should talk to a counsellor and get the options available to you so that you can make an informed decision.

If you really want to go for CSE, then you should accept the fact that it will take a minimum of two years (one for prep and one is the exam cycle) and may take upto 7 years. You should think of your financial condition and then make a decision as to leave the job.

As for job, coding skills do not matter at this point of time. Why don't you join and let the company teach you? They hired you from mechanical engineering background, obviously they knew that they would have to train you. Don't let lack of confidence make the decision for you.

Also take a look at the number of people who have cleared CSE with jobs. It is not impossible and hence, it can be done.

I would just like to add on to the wonderful advice by @thistooshallpass.

You haven't told us your age but assuming you are somewhere between 21-24. I would advise you to work at Accenture for 1 or 2 years. You might end up liking the job. meanwhile, start saving for UPSC prep as much as you can. if at the end of 1 or 2 years you don't like the job then leave and prepare full time with the savings you have. UPSC exam is highly unpredictable more so because of the preliminary examination. so save enough so that you can prepare in peace.