On the bottom left of your keyboard, there is a shift key. When you press this key along with a letter on the keyboard it capitalizes the letter.
How long did you say you had been training?
You mentioned your chest exercises but you said your goal was to get your arms bigger? Granted, the b-press does work your tris, but what do you do for your arms? Let me know and I will give you my opinion.
I too have lifted all my life and I'm 35. BUT, when I was around your age I was in the military and I seen my greatest gains at that age without "help". I think you might need to push yourself more. That is just the vibe I'm getting. FYI.
To gain mass: PUSH IRON HEAVY!!