This is likely an EC that OP finds worthwhile, or at least meaningful.
OP, Lang’s Basic Math was not written to be a first text in the subject of high school math. If you’re seeing things for the first time in Lang, you’re making things needlessly difficult for yourself. That being said, proof based math takes time, and if you are making progress and learning, that’s a good thing. If you want to tone it down a notch, what you should switch to depends on what you know so far.