cool you made a rocket all by yourone
im not a scientist but i play a lot of kerbal space program and am a very logistic thinker (dont worry im not gone atvise you to put on more bosters -w-)
what i think is that your rocket acceleraded to quickly and couldnt stand the heat of the acurating air, like a tiny fersion of re-entery heating, its unnesesary to let it brake te sound barriar specially with a small craft like that.
did you programed the lancing proticol or did you stear the craft manually...?