Are Dietary Supplements Okay To Continue Taking?

Okay, so I'm 13 and on the school's wrestling team. I have been taking two dietary supplements: Six Star Muscle's Creatine and Drenalin . So far, I have not suffered from any side effects, but is there any long term effects? I was just curious because the bottle states not intended for people under the age of 18, and it has actually really helped me. I used to have trouble lifting 10 pounds (Yes I was that weak) but now I can curl 30. Any help would be appreciated.