Ah hey! I recognize your digital faces from another thread. Your sketches are great, your characters are especially good and interesting! Right now, I'd recommend you to be more confident in your lines, drag them out a bit and explore the shapes. Your sketches are pretty, but many are only the very sillhouettes of eyes, noses. There is often more to it than that, wrinkles, eyelids. Explore the depths of the planes, such as the deep part between the eye's caruncle and the nose. You can also form out the shadows with lines to better help you understand how things work! Either way, you are still amazing, especially for your age (I can't even remember being 15!) you're great and I'm looking forward to seeing you develop