Brian wonders if it might be "too soon" for a play about Terri Shiavo, yet backstage when Stewie is hero-worshipping the Matthew McConaughey-based older kid Jared, they establish that Jared played Stewie's part for 3 years, meaning this would have to be at least the fourth year in a row that they're doing this play. If this year might be too soon, it was definitely too soon when Jared would have started, and Brian wouldn't wonder for a play which has gone on for four or more years.
When Stewie has stage fright playing the plug, he wets himself, however it is well established that Stewie still wear diapers (nappies in the UK).