I graduated from BC in 2017 and lived in Coolidge Corner, Brookline my first 2yrs out and loved it! Relatively close to campus and easy access on the T Green Line (street level trolley) but it feels more like an adult neighborhood. If you also want to do more stuff in Boston proper, Brookline is a nice in-between spot. Lots of fun restaurants, shops, and parks in Brookline too, definitely give it a consideration