If pixel art interests you and you enjoy doing it then by all means don't let a defeatist attitude stop you from continuing! If you recognize your own faults and understand that you have room to grow that's all the motivation you need and don't let your mind slip into that dark place, even the best artists can keep themselves from creating masterpieces due to low self esteem.

As I've learned recently, as I'm new to pixel art also, always reference an image for the art you are making. Get a picture of an ice cream cone and plop it down next to your canvas, compare and contrast, notice the lighting, color shifts, shadows and how texture of surfaces changes those things. Start editing your cone by first making sure your overall shape is accurate, the refine the colors you can put them down as solid splotches at this point, once you feel like the shape and colors are right, go in deep and start working out the details. Try to make multiple copies and compare your copies to each other to see what worked in one vs the other.