At 17 yrs old 128 pounds how much should you bench press to gain muscle mass?

Depending on your body type the weight you can lift will vary. Some 17 year olds with shorter arms will be able to curl or bench press more than those with longer arms. Also, a mans muscles will mature at different speeds, some will mature faster and will be stronger than others. So, there really isn't a specific weight that a 17 year old boy should be able to lift. Some will say otherwise but I'm telling you that you shouldn't worry about it.

If you want a specific weight though here's my opinion:

17yr old bad shape: bicep curl: 0-10lbs, Bench press: 0-50lbs, Squat: 0-60lbs

17yr old good shape:bicep curl:10-35lbs,Bench Press:50-120lbs, Squat:60-170lbs

17yr old Excellent shape:bicep curl:35-65lb,Bench Press:120-250,Squat:170-320lb

17yr old extreme shape:Bicep Curl:65---lbs,Bench Press:250---lbs,Squat:320---lbs

That's just based on my own findings and thoughts though. Some may have other points of view.