One reason why Superboy was aged up to 17 is that he could be the inspiration and member of Rebirth Legion of Super Heroes
CBR reports solicitation for Supermam 15
At last it is the return of the Legion of Super Heroes! The greatest super heroes of the 32nd century have traveled back in time… to make an offer but to which hero? And why will that choice tear Superman’s Life apart.
The new Legion will be written by Bendis.
Bendis has the choice like the original superboy to have Jon Kent in both the present and the future but this gives him the opportunity to write him out even though Jon could go to the future for a year and appear 5 minutes later in the future older.
Supersons could still appear like now with it being history told to future descendants.
Jon still appears to be Jon almost a 10 year old in a 17 yesr old body shades of Shazam.
But the Superman family of Clark Lois and Jon appears doomed.