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I would suggest asking an art teacher, or if you have some sort of formal portfolio together, visiting a formal portfolio review event when you have the chance! Sometimes parents and friends just don’t know enough about art to give you a proper critique, and that’s when you turn to the experts.
There’s also online artist communities that can give you critiques if you ask! I’ve heard great things about ConceptArt, so you can give that a shot.
It’s wonderful that you’re looking for constructive criticism to help you improve. That’s a very healthy attitude to have. Keep it up! d(-_^)