Can a 14 year old sleep 7-8 hours per night?
I guess you're 15 now, but the answer is the same. No.
Current wisdom says teens need 9.25 hours of sleep per night, 7 days a week. Regular sleep times and wake times are important. The tough part however, is that melatonin production in teens is delayed up to 3 hours, which means those ‘tired' feelings are delayed about two hours.
My son who went to bed/sleep at 11pm, suddenly started feeling sleepy at 1am...and I thought it was his fault. My bad.
This ‘sleep phase delay' is a natural physiological occurence, and makes getting up early for school a real pain in the ass. Hence, the current public debate around later school start times...which frankly, are all justified.