Diane, don't be overwhelmed by all the questions above, first answer this.......above ground pool or in-ground pool?
Assuming the answer is above ground, then let's talk about size. Get a tape measure, and go out and measure the area for the pool you think you would like. Again, assuming this is your first pool, may I suggest if you want to dip your feet in the water in this pool thing, let's go with one of the framed Intex pools....Metal frame or Ultra Frame. I started out with the metal frame then recently have gone to the Ultra Frame. If your committed for a "real" pool, then start looking at the "big" ones at the local pool store......yup, they can be nice and expensive.
Now you can reread the responses above. All of them are spot on. You really need to see what legal problems may be in store for you with a pool. I would mention homeowner's insurance too. Something you might ask your agent at least. You will need electricity for the pump and salt water generator too if you go that route (it does make it less stressful once you get everything fine tuned with it). An extension cord is a poor option here.......so electric work may be in your future.
OK, with all that said, get to work. Oh, one last VERY important thing. ANY above ground pool will need an absolutely level spot to sit on. If you can't do that you will need someone to do that for you. Again, it is critically important that the site be absolutely level.
Finally, you need to sit down and decide how much "sweat" equity you are willing or are capable of. Many here are pretty capable, but the bigger the pool, the more likely you WILL need help no matter how handy you are. Figure any installation costs now before you start so you aren't suprised.
Keep on asking the questions and telling us your thoughts. There is a great amount of knowledge AND experience setting up and operating pools of all sizes here. Everyone here wants you to have a positive experience with your pool because we have had it with ours and hopefully we can keep you from making the mistakes we have that made.
Bob E.