Welcome To The Forum.
You have come to the right place. This forum, I have found, is an enormous collection of willing people, who combined, have all the knowledge that you could ever hope to need. First off never be afraid to ask, someone will always have some kind of answer for you here.
So lets get started: All the advise I have read thus far is quite excellent.
1.) Here's how a gun works check out this link its pretty much everything you'll ever need to know and then some:
http://www.expertvillage.com/video-series/1854_hand-gun.htm
2.) Handguns in the movies are absolutely unrealistic . . .ABSOLUTELY UNREALISTIC! Make no mistake about it. And first person shooters are fun but they are no better in terms of the reality department.
3.) Eventual kids are defiantly a enormous issue. My advise, if you eventually have them would be go a little overboard when it comes to safety. You can never be to safe! Get yourself a trigger lock like these:
http://www.gunaccessories.com/CCL/index.asp If you have little interest in actually using this gun in order to protect your homestead, and it is primarily for recreation in your hands and nothing else, by all means, with kids around don't stop there, go for broke: On top of the trigger guard also lock up your gun in a case and put the only key on your key chain or someplace else safe, put that case up high in a closet where they can't reach it, and ALSO lock up your ammo the same way in a second case separate from the one that holds your gun. That is a little bit over kill but when it comes to my family that's the way I prefer it, so I would recommend it should the stork fly your way
.
4.) Defense of the homestead, life and property however is a whole different story all together, if your desire to here about that, post back that you would and I'm certain many would be willing to share there views with you.
5.) If your gun is solely for sporting purposes alone than a .22 is pretty much the status quo. Easy, cheap and fun---can't really beat that! (though would not be the first choice if home defense is a consideration for you.)
6.) Now we get serious. This is THE MOST IMPORTANT THING . . . DO NOT I repeat do not EVER point your gun at anything that you are not willing to blow into oblivion! Always assume it is loaded. Never ever point it anywhere but at the targets at the range down range. Always assume it is loaded at ALL times. Accidents happen when people don't adhere to this code of conduct. The gun's safety is there for a reason but NEVER assume that it renders that gun perfectly safe or inert, always treat it as if it were loaded and ready to fire even when the safety is on. And yes even when its unloaded to. If you do this religiously you will never have a problem 99.9% of all negligent discharges (that means gun accidents) happen when people start screwing around and stop adhering to this code of conduct.
7.) Misfires WILL happen. That's when you pull the trigger and instead of a BOOM you get a click. When this happens always remember to keep pointing that gun down range. And wait at least 60 full seconds before you attempt to rectify the problem. There are such things as slow primers and sometimes like a rogue firecracker the bullet may actually be slow to fire. You can always pull the trigger a second time and see if that fires the bullet but if it does not wait . . . A full sixty seconds . . .while pointing the gun at the target . . . down range . . . .before you attempt to rectify the problem.
Do this and you'll have nothing but fun with it as well as a lifetime of healthy recreation. Follow these simple rules and you'll be ahead of many people at the age of 21 in terms of gun awareness and safety. Also one last thing DO NOT get involved in the macho silliness of caliber wars. If you want a .22 go for it, it a great gun especially recreational purposes. You will likely get snickers and comments about how small the bullets are but those guys are just blowing wind.
P.S. Also if you are going with a .22 and you love first person shooters check out the picture link below you have got to check out this gun! It is the .22 Neos from Beretta (just google it) and its about the coolest looking space gun on the market. Seriously the Master Chief himself could be carrying this thing . . .
Have a good time shooting . . .