The Real Reason Why Teenagers Are Always so stressed

I know the real reason why teenagers are always so stressed, trust me, my brother is nearly 14.   Can I tell you, something? Well, I don't want you to know what it's called until your 11, so lets just say there going through some changes. I notice he's gone through some real changes.  His voice got deeper (When I was 4, it was really, well, squeaky) and he can't do flips like I can anymore (It may just mean he's less healthy, I don't know).  My voice will never get deeper, cause it never has.  My voice sounds like a mixture between girl and boy. (My Mom says mine sounds younger than it really is, but I don't believe this).