Lyric discussion by LRonHoover 

Cover art for 17 lyrics by Jethro Tull

One of top 5 most underrated Jethro Tull songs. Not sure I have much to add on the meaning, other than the fairly obvious. A young man longing for the days of carefree non-assimilation and beginning to sense immortality and rules that have to be complied with. The "cakeman" is a reference that is lost on me.

@LRonHoover Urban Dictionary a few examples. A married man who strings along single girls with promises of a future relationship- ie. having one's cake and eating it too. second example: A male who spends too much money on females. Comes from the work caking.