al-Baihaqi's narration has:

"He did not give me permission (to fight), and did not consider me has having attained puberty." [Ibn Khuzaimah graded it Sahih (authentic)].

وَفِي رِوَايَةٍ لِلْبَيْهَقِيِّ:

فَلَمْ يُجِزْنِي, وَلَمْ يَرَنِي بَلَغْتُ

.‏ وَصَحَّحَهَا اِبْنُ خُزَيْمَةَ [1]‏ .‏