• Don't get the full "super-dooper" version, get Photoshop Elements. I've been using Photoshop Elements exclusively for over a year now, and it does everything I need. And I'm a pro! You can get it for cheap on line, I've even seen it at Costco. By for cheap I mean, a fraction of the cost of the full version, which is over $500.
• Don't get an old version or a "bootleg" version. Sure, we all want to save money, but this is false economy. It won't work right if you do that. You will spend a lot of time trying to get it to work, and it won't. Don't do it. Get the current version, which is about $100, install it on your computer and register it with Adobe. No, this has nothing to do with morality, or Santa watching you, it has to do with being able to get on with your life. Install the software correctly, and you can begin having fun with Photoshop.
• Don't bother with a beginning training session, just turn it on and start to play. I've taught beginning Photoshop, and it's mostly, here it is, enjoy! For advanced stuff, which you may or may not ever need, yeah sure, go to a training session.
If you're elderly, that is over 12, you will want it to be something else like Microsoft Word, and you will fight it. Kids pick it up fast because they have no prejudices. You can do it, too!
No, Adobe doesn't pay me to say this stuff. I just want you to be happy, and have fun!