I Am Trying to Lose Weight

I keep craving junk food. My family...well some say I dont need to lose weight and remind me that I'm very tall and I dont need to weight like the average and short girls and flat out told me I need to weigh more. They are unsupportive of my weight loss but some people are supportive and want me to get healthy. I dont understand how can I lose weight when some people dont want me too? It kills my confidence to do so. I just wanna fit well iin clothes and not lose my breath quickly. I'm 6'0/6'1 and 230lbs. NOBODY BELIEVES that I'm 230.