Yeah I could say a lot about that. Discrete or Intro to Proofs is where math starts to get serious at the undergraduate level, you could say the same about analysis, but the techniques used in analysis are what you learn in discreet. What's really cool about that class is that it opens up all sorts of areas of mathematics to you, where as before discrete the track is pretty linear: pre-algebra, then algebra, then pre-calculus, then calculus and so on. That track continues through Vector Calculus, Ordinary Differential Equations, Nonlinear Dynamical Systems, Partial Differential Equations and so on, but there are a ton of other really interesting classes that tend to only have Discrete as a prerequisite (Linear Algebra, Abstract Algebra, Higher Geometry and so on). If you know some basic calculus, discrete also equips you with everything you really need to start digging into analysis, which is where math really gets interesting imo.
It will probably be pretty different from math classes you've taken in the past, and you may find it particularly challenging even if you are generally good at math. The inverse may be true as well though, I know students who had a really hard time in math generally and then began to excel once they got to proofs. I can't say if this will be the case for your class, but in the experience the workload tends to be quite a bit lighter in terms of homework, the tests don't have so many problems on them, and there isn't nearly as much computation involved as in something like calculus or algebra.
Unless you had a really good geometry teacher or have a background in computer science or philosophy it is likely that some of the ideas presented in the class will be pretty novel to you. In earlier math classes there are shortcuts to doing well in the class if you don't understand the content: memorizing formula, grinding problems etc. There is no way to fake proofs. My first advice is to have a system for taking good notes. If you have a hard time taking notes, look into finding a way to record lectures or get notes provided. Look over the notes regularly, use a highlighter to mark certain definitions that come up regularly, and rewrite new notes as you go that takes the most important concepts from your previous notes.
Next is to read the textbook, and utilize office hours if they are available. Between the book and your professor, all the answers to questions you might have are yours for the taking. This really goes for all math class at the college level, and is something I wish I had taken to heart when I was in school.
Third is to write things out in plain English rather than only in mathematical notation! People don't tend to think in mathematical notation, so it's hard to understand the math you are doing if that's all you're writing down. This also goes for math in general, but people tend to look at me funny when I recommend this for classes before discrete or proofs.
In terms of preparation the best thing you can do is to start reading the book ahead of time. The hardest concept is going to be different for different people, but when I took the class I remember a lot of people struggling with proof by contradiction, so you might want to look into that ahead of time. I've attached a textbook (second attatchment) which is actually a book on analysis, but it also contains an introduction to proofs which is the part of the class I am familiar with (I think discrete also includes some other content but I could be wrong about that).
Good luck and if you run into challenges feel free to post questions in this thread and I'll do my best to help you out.
(The first attachment is a book on real analysis, just for anyone interested)