I’ve read a few contradictory reports on the social scene at wellesley, so: can underage people drink there? are people generally only focused on work? if i wanted to, say, play board games and drink a few beers with my friends, is that type of thing expected at wellesley?
There’s not as big a party culture at Wellesley as there is at some other LACs, but you can always find beer on the weekends. My daughter didn’t drink much when she was underage, but had no trouble getting access to alcohol when she did want to drink. 
She was so stressed about finals her first year that her RA gave her some rum in a mug of hot cider!
This year, every time there’s a presidential debate, the wine flows very freely, I’m told.
But yes, you’re also correct that people are very serious about their work. It’s an intense culture, as you’ve probably heard.
The town of Wellesley was famously dry but now several restaurants have liquor licenses. Boston’s Puritan roots (look up “Blue laws” that were in full force when I was there) and concentration of college students means more serious enforcement of the legal age than in other places like New York City. This background may explain the “contradictory” accounts. On campus upperclass women help out with orders of “booze”, and sure, bring on the Scrabble board!
Trust me, underage people do drink. In my opinion, the work hard, play hard attitude is a very good description of what Wellesley is like. The “play hard” part may not be quite as hard as at traditionally party or sports-oriented schools, considering Wellesley IS a primarily academics-focused institution (which you WILL feel very hard while on campus), but that is not to say that people are only focused on work, though such people certainly do exist at Wellesley.
Like doctorgirl said it’s work hard, play hard. On weekdays Wellesley is pretty dead but come Friday afternoon, most partiers leave campus, ppl hang out for Netflix and chill and others just get to sleep in. Come Saturday, dozens of (attached) guys walk campus :)) :)) :))