Yeah if you look a little older than an undergrad you’ll just be mistaken for a grad/professional student. For study spots I’d go for G Cafe on Chapel or on Orange. A nicer spot away from Yale is Pistachio. The original one in Westville. They have a new location on Chapel and Howe that looks nice in photos but I haven’t been. And there’s always Mamoun’s but I don’t know if they have wifi or not.