That seems to fit actually, despite how it ages Bruce, Dick definitely seems to be portrayed as being in his late 20's so seven years younger than that is early 20's. It only seems like an issue because, like Tim, Beastboy often gets depicted as more of an adolescent than he should be though in Dark Crisis and the latest issues of Nightwing Gar does actually look mid-20's for once but that's not the case most of the time.