When I started martial arts I was 13 and could not even touch my toes and was nowhere close to doing splits. Three days a week we did stretches and within about 3 months I was able to put my palms on the floor. After three years I could do full splits to the floor. Ligaments and tendons take time to stretch. I just started but I’m very confident that if I’m careful and do the exercises regularly that I will see gains. Bodies just take time to adjust to the pressures. There are people that can put their bodies into a pretzel and they certainly didn’t learn to do that overnight.
I’m personally going to take it VERY slow as I like my penis in full working order without red dots or thrombosis veins. I’d rather have no growth than an injury so if it takes me three years to get a half inch so be it. Good luck!