Commute advice please: green line b

I just moved and everyday I will go from the west side of green line b to Arlington t stop and back home. At 6pm I try to get on green line b headed west so I can get home, and I waited 25 min for 3 b trains and they were all too full to even get on. It’s like that until Boston university central I swear. How can I make my commute home easier? Should I walk to a dif t stop? Whats the solution? It can’t take me an hour to get home everyday when it’s a 15 min t ride. Also where are all the BU students going all day long that they’re also heading home same time as me? Why so packed? What am I missing?!?