Hi Aastha,
I hope you haven’t been waiting on a second opinion to make your decision?! I completely agree with Christine’s comments. Add to that the numbers of people who change the their major while in college, work in fields not related to their degree and/or change jobs/careers! I would suggest starting with the broader degree (Mass Comm) and explore internships, talk with my advisor as well as seek conversation with those already working in Advertising.