The Standard Answer #1:
Find a range where they will rent time on several different pistols, and try as many as you can afford to rent.
Choose the one which seems to best suit your hands.
Don't worry about accuracy: All modern pistols will be inherently accurate enough for your purposes.
Standard Answer #2:
Small, easily-concealed pistols are very difficult to shoot accurately, effectively, and well.
You will be best served by choosing a larger pistol than you think you need, because it will be easier to shoot and to control.
You will be surprised at how easy it will be, to conceal a large, easy to control pistol.