I am 46 years old and I do not think you shrink.
In fact pop a viagra then measure it, I bet you get all your 6 inches back and a bit more.
Don't worry yourself about something that is not there.
I see undue stress and gear does not make the willie shorter it only makes the balls smaller, hell that might even make the willie look longer
I notice on a test cycle I practice that jelqing every day without even knowing what it was
Don't stress bro, some things are not as they seem, don't lose any sleep over this one.