Camera RAW is an amazing thing, and I highly recommend you shoot in RAW format. The image sizes will be larger and less compressed because what camera RAW does is saves all the information the sensor (the thing that 'sees' your image) has, not just a fraction of the information which is what happens when you shoot in JPG. The best analogy I can give is let's say you are making a dress for your best friend. You can either get a pattern that allows you to use multiple sizes and adjust well, or you can guess a size and try to adjust later. The pattern is going to work much better, but take a little more time and care. This would be shooting in camera RAW. Buying a dress and hoping it fits or that you can make minor, tiny adjustments later is much easier, but can have bad results. This would be shooting in JPG. The other way to think of Camera RAW is like a digital negative. Back in the day, you would manually expose the negatives in machines. The negative captured all the information, and you could do a lot with that.
If you are starting out, try mastering some of the other techniques first. Editing your photos should come after you start understanding some basic terms and ideas. Once you have some things down, and you want to be able to have control over your images while sitting at home, switch over to RAW.