Hi,

As per your saying you wanted to pursue BBA LLB and this course is available at Law School of UoM's Thane Sub-campus, So, it's a win-win situation for you. Though University of Mumbai Law Academy would have been better choice and with your rank of 180 you could have easily got that too. But now I would like to tell you that, first thing, which one needs to succeed is the passion and you have got for this course, so now your should go for that. I would also like to tell you that as you gave UoM Law School first priority and have got that you don't have the option of backing out. Because 

(9.3) During the CAP.—(a)If a Candidate is allotted the seat as per his first preference, such allotment shall be auto freezed and the Candidate shall accept the allotment so made. Such Candidate shall then be not eligible for participation in the subsequent CAP rounds. Such Candidates shall then report to ARC for verification of documents and payment of seat acceptance fee through Candidate‘s Login. Thereafter such Candidate shall report to the allotted institute and seek admission on the allotted seat. If such Candidate does not report to ARC for confirmation of seat acceptance, their claim on the allotted seat shall stand forfeited automatically and the seat shall become available for fresh allotment. For such Candidate, the allotment so made shall be the final allotment;

So, Be happy and join the course of your choice at your prefrred institute, Best of Luck for future!