I am a high school student that wants to be a paleontologist. However I have a question: is it even possible to know every single prehistoric animal name? There are so many of them, not just dinosaurs, but other prehistoric creatures as well! In my case I am mainly interested in dinosaurs, so how much should I know about, for example prehistoric sharks, or animals from the Permian (when there were no dinosaurs), ammonites, prehistoric mammals, amphibians, etc etc... I suppose I must know basics about them, but every single species? Should I know that as well? And any tips on how to more easily memorize dinosaur names would be much welcomed.

If you are going to get a PhD, yes, you will be grinding your way through memorizations of those names. It's a lot like medical or law school - you cram, take tests, and forget what you don't need for the next courses. As you go through each year, you will specialize more and more and be able to concentrate on what YOU like, not what you have to learn.
The best way to learn all those names is to know how they were named. That means learning a bit of Latin, and often the names of the people who first found the fossils.
I think you are worrying about the wrong things. Have fun for now, learning about the latest finds, visiting museums, seeing if you can volunteer on a summer dig! Interest will drive your ability to memorize.
And last but not least (sorry to be a downer again), becoming a dinosaur specialist is a LOT of other science too - from geology to chemistry.

Study, study, MORE study. Takes YEARS of study to be an expert, and then more study on top of that. NO, you will never stop studying, NEVER, ever because there is always more to learn.

Have fun. :D

It has been estimated that the total number of species of animals alive today lies somewhere between 3 and 30 million. Looking back through the evolution of life on Earth it has been estimated that only about 1/100 of all species that ever existed are still alive today, so that means somewhere between 300 million and 3 billion species have inhabited the Earth. Of course we have names for only a tiny, tiny fraction of these, but as more are discovered in the fossil record there will be more names. I read somewhere that now there are something like 12000 named prehistoric species. Can you hope to learn them all? Good luck ....

Thanks for your answers everyone :) I have a lot of questions regarding palaeontology, so if you don't mind I'd ask one right now: can someone tell me how to correctly pronounce the following: tyrannosaurinae, tyrannosauridae, macronaria, tetanurae, coelurus, coelurosauridea? I'm from a non-english speaking country, so I am not sure how to pronounce those. Also, any helpful links you might know about cladistics, taxonomy, etc... Thanks again!

The pronunciation as actually driven by the Latin roots of these names, not English. In general the dipthong "ae" is pronounced like a long I, "au" is pronounced like the 'o' is sore, and 'coe' is with a soft c, like 'se' in "send".

You can try using this site for pronunciation of Latin words - although it doesn't have all the words you're interested in, there are many that are close enough to give you a good idea: Pronunciation of coenozoic - how to pronounce coenozoic correctly.