I’d think of it this way: what do the two cities have in common, and where can I tilt the scales.

Both cities do seafood well. Both have a lot of bars where you can meet people at the various schools in the region. Both have high concentrations of schools so there are a lot of young people around.

Here’s where they differ, however:

Boston is close to NYC prices; Baltimore absolutely is not. Boston is on the far end of the Amtrak corridor (can only really go down to NYC) while Baltimore is more central (can go to Philly or DC equally easily); Boston has an insufferable accent, Baltimore… ah, Nevermind. In all seriousness, Boston has a moderate crime issue while (some neighborhoods in) Baltimore have more serious crime issues.

Long story short I think it just boils down to: Baltimore is more affordable and you’ll have an easier time being an adult here with your own space than you will in Boston.