Well, there’s not much you can do about the passage of time without affecting everything–it wouldn’t be enough to rejuvenate Peter, you’d need to do the same to his entire supporting cast, and then you get into questions of the rest of the Marvel Universe–so it’s really an all-or-nothing proposition.

That all said, in the 21st Century, 27 is a lot younger than it was in the 1960s. These days, when many young people are living with their parents longer, marrying later if at all, and moving from job to job in short spans of time rather than sticking with one company for an extended duration, there’s still plenty of growing up to be done even for somebody in their mid-twenties. (How many successful sitcoms of the past 15 years has been about this very fact?)