I had a tent fly do exactly the same thing. The "age" of a tent depends on its use, not actual age. Mine had spent 30+ days at high altitude (Mt. McKinley). Ultraviolet rays really deteriorate the tent fly. You said you did not care if it is waterproof. I would just use it for now. A heavy dew would still cause small drips. Take a sponge to wipe up the drips.