As far as graphics go, you have no need to worry when it comes to switching to PC gaming. On console, graphics can be pretty impressive. But I don't think any gamer is ever really exposed to high-quality graphics until they try gaming on a well-made PC. When you're playing a video game on a computer, it is much easier to adjust the quality of graphics of your games, as well as adding mods to make them even more realistic. Most of the time, any game you're playing will have some way to improve the realism and appeal of the graphics, even if it's a bit of an out-dated game. I switched from console to PC about 2 years ago, and I have never had any problem with the graphics of my games.
The transition from console to PC may be a little difficult, however. When I switched, my biggest fear was going from a controller to a keyboard. It certainly took a little bit of practice, but it was not nearly as much of a struggle as I thought it would be. I suggest starting out with some games that have minimal controls, so you can get used to the basics of keyboard controls. Then, once you're used to that, playing any other game should be relatively easy. Of course, with any game you may have to learn a few new controls, but adapting to that would take no more than a day. Even if you are struggling to use a keyboard for gaming, you could always just plug a controller into your PC and use that instead! It might not be efficient for all games, but for most it will work fine.
In the end, PC gaming is probably the best option for most gamers. It adds more customization to nearly any game you play, improves the speed and quality of gameplay, and adds many more possibilities to what you can play and how you choose to play it. I thought I'd never use a PC to play video games, but ever since I tried it, I have loved it way more than i have ever enjoyed gaming on my PS3. As long as you're willing to get a high-quality PC with the right parts that suit your needs, I think you'll really prefer PC gaming over console when you're used to it.