Im 14, 170cm, 5'9, 55kg, I'm a bit worried, I don't lift too heavy
No it will not stunt your growth if you do it correctly. Only things That do stunt growth are steroids, some supplements(not protein supplements), bad diet and injuries(avoid injuries by using perfect form on all of your lifts, if you can't use good form you are lifting too heavy .
Lifting doesnt stunt your growth unless if u are lifting too heavy in fact u can grow taller by lifting weights because ur releasing Growth hormone which is a good thing n some athletes have been lifting weights from a young age ex. (Arnold schwarzennegger 6ft, shaquille o neal 7ft) n they arent even close to being short lol the only thing that stops u from growing is bad nutrition, lack of sleep n no exercise
How Heavy, is Heavy? So heavy that I cant do more than 2 reps?