hi
when i was that age, my mum had to constantly tell me that i smelled.
she would buy deodrants, tell me to shower more etc.
the clincher was when she came to find me when i was out with some mates one day, and tell me i needed to wash. in front of the mates.
ok, a bit extreme (i've posted before about my mum,lol)
but she was probably desperate, and it did work
in my case, the reason i didn't listen was that i was the earliest developer in my class which really embarassed me at that time, so my reaction to this was 'denial'
if i pretend i'm not in puberty, it won't be true, lol
as others have said, one or two years down the line, you couldn't get me out of that bathroom, showering twice a day etc etc, lol
hth