To be fair to NYCFC, if you look around other leagues, for example the bundesliga: The youngest player to debut was Nuri Sahin at 16 years, 11 months. Scally is still 15 years old.
By european league 1996 or later to match with mls,(if parenthesis,the youngest of all time):
Premier League: Matthew Briggs: 16 years, 2 months, 4 days
Serie A: Pietro Pellegri: 15 Years, 9 months, 5 days (Amedeo Amadei (1937) 15 years, 9 months, 5 days)
Ligue 1:
Albert Rafetraniaina: 16 years, 27 days
Bundesliga: Nuri Sahin: 16 years, 11 months, 1 day
LaLiga: Fabrice Olinga: 16 years, 3 months, 6 days (Sanson (1930) 15 years, 8 months, 11 days)
MLS: Freddie Adu: 14 years, 10 months, 1 day. (Next closest is Davies at 15 years 8 months, 15 days, and after that is above 16 years.)
you can see between even the top leagues it's not common to play someone as young as Scally, so I completely understand why we haven't played him yet. As for Sands, he's now 18 so I'm hoping we see more of him, or his talent will just rot away... But I think he can become one of our top players if they give him the chance.