Rav Charlap in his haskama to the sefer Pri Yehoshua [from Rav Eichenstein St. Louis 1949] writes a חידוש נורא! The whole idea [according to the Rambam] of a גר קטן being מוחה on his גירות is only if he wants to become a גר תושב!! Otherwise - it doesn't fly.
Rav Y.Y. Weinberg [the "Sredei Aish"] was not thrilled with this idea - to say the least. This is what he replied:
