Should I learn Object Oreinted JavaScript before learning TypeScript?

Short answer: Yes - IMO. You will need it for typescript's extension of JavaScript's objects and classes. As well as many other things. Additionally, typescript doesn't won't give you a good understanding of how programming works, learning JavaScript will.

The only way that I could see you learning Typescript before OOP, is when you come across something new. (For example Classes), read the typescript documentation on what area of JavaScript it extends. (In this case class-based object-oriented programming. Then learn that concept well before learning the TypeScript part.

Having a little bit of knowledge of how things work might be indeed handy, because even if you use TypeScript your code will be compiled into JavaScript at the end.

Learning typescript is a good thing because you'll at the same time learn ECMAScript 6 features.