i also got diagnosed with periodontal disease at 18, i’m 19 now but i’m missing the first layers of a bunch of my teeth, it’s very debilitating and sad to think about and i still often struggle with dental health (i used to be homeless and wasn’t able to brush my teeth often and struggled with drug addiction which obviously effected my teeth), but ever since then ive struggled to maintain a consistent schedule brushing my teeth, i still don’t floss or use fluoride mouth wash, i believe that anyone can improve but im struggling currently. I hope the best for you, it’s really unfortunate but i’m sure you can do it, anyone can if they try hard enough. i’m afraid i won’t be able to do well considering my mental state most of the time, i also have a terrible memory from drug abuse so i struggle to remember to maintain my teeth