I tried that when I was your age and it didn't work that great for me. I did it because I was just so tired after school that I crashed for hours when I came ba

I tried that when I was your age and it didn't work that great for me. I did it because I was just so tired after school that I crashed for hours when I came back. My problem was that I overslept (2 to 4 hours) during the nap and I felt so refreshed I wasn't tired until 2am. So I ended up sleeping only 5 hours for the night, pretty much like you. On the other hand, I was still tired during the day. My point is that naps are good but at some point they're harmful for your night, and 3 hours is getting close. I believe it's better to keep at least 7-hour nights and have 30- to 90- minute naps. But the truth is that school hours are poorly designed. This is a kind of biphasic sleep by the way.