Well sure, anyone can learn how to build up bikes but... expect to pay a lot more than if you just bought a bike at a bike shop.
You're going to need to buy tools, specialized tools for bike work. Some tools you'll have but expect to buy quite a few the first time around.
You're going to make some mistakes. They, again, will cost you some.
There's nothing wrong with having tools and making mistakes. It will also take you time to learn but all in all, I deeply enjoy working on my bikes and building them up piece by piece. If you're goal is enjoyment, go for it. If you think that DIY initiative is going to save you money, it rarely will (maybe a garage sale or Goodwill find).