Overall it's a good computer, but keep in mind that it is 8 years old and when you buy a $50-$100 laptop, you'll get what you paid for. The battery life is meh, and any kind of graphical work (gaming, video editing, big Photoshop/Illustrator projects...) is a bit too much for it. But, for any kind of basic school/office/internet stuff, you'll have no trouble. I try to only have a few things open at a time and I hardly notice any lag. I've only got 6GB of RAM but I'm about to get an SSD and some more RAM, you should do the same if you can.
One thing I would say, people often suggest using an old version of OS X on these slower computers. Don't bother with that. In my experience, anything from Mavericks to High Sierra runs just about the same.
A really big plus is if anything goes wrong, you can fix it for next to nothing. Broken screen? $50. Dead logic board? $40.
Good luck with your purchase, it really is a fantastic computer and I fully intend to use mine until the end of university (in grade 11 now).