If you are writing complete songs and you are a teenager, I think it is less about the actual material you produce than the process and growth you are experiencing. Everything you write now is helping to find and define your voice... that is good no matter what.
Anything is closer to a masterpiece than nothing. Keep going and don't worry about the "test of time..." it is irrelevant to this very moment at which you may worry about the future or be present with your creativity.