1. Join TCS, get some experience nd appear for CAT yet again. or
2. Join MBA@IIT-Roorkee. I don't have any other option 😞
I do not know much about IIT-Roorkee MBA. So my opinion on the institute is going to be very superficial. In IIT-R, the mix and exposure that you are going to get will be very narrow as it'll be just engineers. Besides, the class strengths are quite low as well, so a variety of opinions and learning might not be there. However this might come in useful during placements. Also, IIT-R isn't as highly placed as the other IIT MBAs like Mumbai, Delhi or Kharagpur. However, in terms of ROI, all IITs are going to be good. So my advise would be to try for better ranked institutes next year.
Now some myths and realities about TCS, which you might already know, but I'll restate it.
1) As you've said, bench duration in TCS will be quite long. Not only that, if you're a private tier 2 college recruit, your call letter might arrive late as well. Honestly, many would prefer this as this could be used wisely for entrance exam preparations.
2) However, IF and when you're mapped into a project, the time you're going to get for preparations, or for anything else as such, is going to be minuscule. It becomes mechanical and monotonous, and there's usually no time for anything other than work. Again, this depends on the client account and project you're mapped into, but in general, it's hectic.
3) The so-called 'corporate' experience is hyped. It doesn't come to you. You have to take hard, conscious efforts to seek it. You need to make your own efforts and find channels to learn about the business end of processes and projects. Otherwise, your nature of job usually involves Excel sheet works or e-mail sending, or Testing, or likewise monotonous works. This again, depends on if or not you get into a good project. There are good profiles as well like Business Analytics, but very few people get into it.
If you're seeking a career in Marketing, then it would be better to do your MBA as a fresher since most Marketing companies prefer freshers.
Also, the unpredictability of CAT is something you should take a decision on. You have the age and you could as well give more attempts. Besides, CAT isn't the only examination.
All the best 😃