I am a creature of habit when it comes to sleep. My high school schedule determined that I'd have to wake up early every weekday morning. Sleeping until noon seemed unimaginable to me back then.
In university, I had a lot more free time on my hands, so I would sleep longer. It turns out, however, that adults need about 7-8 hours of sleep and not 9-10 hours. The medical advice on the Internet makes this very clear.
It's odd, but being in university allowed me to be the teenager that I couldn't be while I was in high school, but with the degrees in hand, the alarm bells to become a responsible and healthy adult are ringing loud and clear.
It's not such a bad thing to grow up. It's okay to have more discipline about sleeping hours.
According to my research, the quality of sleep matters. Reducing caffeine (I do love my tea) is probably the most effective thing I can try here, though there are other useful tips here.