Am I doing something wrong?

i started weight training last august and i've been usually training arms, shoulders and chest heavily since the past 8 months because i felt my upper body was really weak. When i first started, i was about 85 kg(187.5 lbs) and my upper body was quite skinny due to being long(203cm|6.66feet). Now i weigh approximately 101kg(202lbs). when i started training, i started with 10 kg dumbells for biceps( 10x5-6 reps), 7.5kg dumbells for triceps(10x5-6) 25 kg bar for chest(10x4 reps) and 5kg dumbells for shoulders(10x4).

Now i am currently working with 22.5kg dumbells for biceps(10x6), 30kg bar for triceps(13x5-6, mostly skull crushers), 25 kg dumbells for chests(10x7-8), and 10kg dumbells for shoulders(13x8,usually lateral raises and shoulder presses). I also pay attention to my form during these workouts and i usually take between 1.-1.5 minutes, 2 minutes at most between sets.

My main concern is that whether or not im doing something wrong. I really didn't think i could improve this much in 8 months. Is my progression normal, or am i overlooking something?
And also i would be very happy if you could givesome advice for my workouts. regarding what body part i should focus on more.