Hello aspirant, hope you are doing good.

Firstly, congratulations for your preparatory rank , you got an additional chance of getting a seat in IIT, next year. So, as you might be knowing, the preparatory rank is just to get into preparatory course, you will be taught for a year in any of the IIT that you get in the counselling, and at the end of the year, you have to qualify for the exam, and if you pass, you will get a confirmed seat in the IIT. Now, whether or not you want to take up this preparatory course is upto you, you might even rather drop the year, but this chance of being taught in an IIT is a big deal, you shouldn't give up on this. This is just my opinion, you can do what suits you.

If you want to know about all the possible colleges you can get into with your JEE Advance rank, you can get it here:

https://engineering.careers360.com/jee-advanced-college-predictor?icn=QnA&ici=qna_answer

Hope this helps you. Good Luck!!