It took a few years to really get used to the quite literal "maintenance" puberty causes. It happens at different times for everyone, as though it's a ticking time bomb that someone else has the control over. It's not necessarily at the beginning of puberty either, and for some it comes before that transition even occurs & for others like myself, it comes fairly late.
My clock started when I was sixteen. I know, real late, right? Anyways, I was in third period, math to be specific. It's not a weak subject, but I never had much interest in it. It bored me in fact, but I did my best to keep up and stay attentive. It helped in other areas too. Like keeping my more erotic thoughts in check. I had this weird idea that if I just avoided it altogether, it would never happen to me. A life without sex of any kind wasn't so bad. At least you didn't die spontaneously. Still, I was a teen with raging hormones, and even without thinking about it, I'd get a hard-on for no reason at all, at any time of day, no matter the situation. My dad warned me it wouldn't help to avoid it altogether, it would actually make it worse. Hed say "Jo, you've at least got to do it yourself, otherwise, it will make your life hell before your clock even begins. Besides, it will be good practice! So, you know, think about it." I still haven't ever tried it. I guess I'm too afraid of breaking my long absence of the subject, and accidentally starting my "clock".