chewing gum will only make things worse, it's mostly a made up thing so people can sell you "hard gum"..
you need to get evaluated by an orthodontist, i know your mom isn't supportive which is tough so you'd need to figure out a way to convince her. misaligned teeth and jaw recession is especially easy to fix at 14, so good treatment can genuinely change your life. You're at a stage of life where changes actually stick. Other than that eating healthy food (nutrient wise) and good tongue posture will help.