22 year old here. I fall asleep instantly around 11-12, and up until recently, I couldn't nap during the day. A few weeks ago I took a nap after coming home from work at 4pm, woke up at 5pm and was amazed at how good I felt. So now I try to make that a daily thing. It not only gives me more energy for the rest of the day, but it also boosts my mood an incredible amount.

I couldn't take naps when I was your age either, but eventually became extremely able to take naps :)