Apple stopped including the laptop lock slot quite a while ago. The last MacBook Pro to have one was the 2012 model with the built-in ODD. None of the current models offer this feature. Just checked my 15" 2012 Retina and no slot there either.
My suggestion is making sure your parents have a rider on their HomeOwners insurance covering loss/theft or damage if you are in a dorm room. If you are living in an apartment, then you need Renters insurance. My daughter spent less than $100US per year for coverage.
Best advice is to NEVER leave your computer alone in a public space. Lock up your living space if no one else is there. In the time it takes to visit someone down the hallway, that is more than enough time for someone to step into your room and grab your computer, iPhone or iPad.