I think the question you are asking is if using resistance bands will impact your height negatively. The answer is almost 100% no. For a resistance program to negatively affect height, damage to the growth plates of the bones and/or extreme overload stress would be necessary.
Your height is governed by genetics. But environment also plays a big role. Nutrition and environmental exposure are the big players. Poor nutrition will affect growth. And exposure to toxins, especially pollution and cigarette smoke have been shown to negatively affect height.
This all applies to the growth phases of our lives. Males at the age of 18 are usually in their last growth phase as far as height is concerned. Females are generally ending their last growth phase by 18, if not already at the end of their height limit. It is unlikely that you will affect your final height very much at 18, but if you use sound nutrition and exercise you can make a final growth spurt count. And 18 is an excellent age to make an impact on your future health and fitness. Creating positive habits, both nutrtionally and exercise wise, now will make the future much better.
Adding to the above answers you might want consider on the below; pl do some research then find a qualified person in your local area
Dr,RD, & strength coach with experience .
1) Sound flexibility program covering the entire body. When you do improve your posture you might be able to stand a bit taller
2) Structural loading with resistance training under supervision might lead to some kind of a height increase only if your bones are still not fused
3) Exercise programming with proper rest/recovery in conjunction with Nutrition quality, density , quantity will maintain your body in anabolic hormone environment for growth & repair .
last but not least Genetics factors, over my 20 year careers I have coached few kids with bad genes who had a height increment there is no solid evidence proving the above 1-3 if done safely with a good team only positive factor at least you given your best effort .
Hope this helps.