that is the biggest myth about weight lifting. no scientific study shows that this is the case. of course doing TOO much of anything can cause injuries. So, weight lifting does not stunt growth, but you need to make sure that you are lifting right and in the correct form to prevent injuries long term. dont lift weights more than 5 times a day. make sure you rest properly and get in the habit of following a diet RESEARCH DIETS, they are more important but weights finalise it. if you make a habit out of getting a routine it will be easier later to have discipline.
Dont listen to these people who say, " youre fine, you will grow out of it". they are the ones that never tried and are bums now. you need to take ACTION right now. dont worry about timing. just be what you want to become NOW. life is short. take control. If you leave it till later, it will become more difficult because of the natural concept of age.
you should research creatine and how it will help you. there is no age restriction on it. in fact you can buy it without your parents consent. im not saying you should do this but you should research it thoroughly, use good sources, convince your parents to buy it. they may not listen to you but they will listen to science. sometimes parents believe in stupid myths, and its hard to convince them to have an open mind. keep in mind creatine can help but you need to be working out for it to actually have a real impact. also for weight lifting and cardio, you should be doing both.
but do NOT take my word for it, research for yourself and verify. never take things at face value.