Stick with 45acp unless you have small hands that cause a problem with proper grip control. If grip control is an issue with small hands the 40 S&W is a great caliber also. You might check out some other pistols, the S&W M&P is a great gun, as are the Springfield armory XD's. Don't just buy a glock for the name, go and handle all of these models and shoot some at a range if possible. I couldn't wait to own a glock, and once I had one I found out it would bite the web of my hand when fired.