Not at all, my hands are big, I have thick and imprecise fingers, but a 4inch screen is perfect for me, keyboard does an amazing job autocorrecting my mistakes, it is funny cause I usually see the screen where the words that I'm typing are, but when I see what my fingers are doing while typing, well, they are far from accurate, it does the job.
I can assure that there is a myth over larger screens are easier for typing, actually in a larger screen the distance your fingers need to travel is longer.
Give it a try, it kind of magical