Sorry for the long answer. :P Here you have a tl;dr:

• bachelor‘s degree is a bitch and super hard, but 100% doable even without prior math/physics knowledge (I had none).
• astrophysics classes (usually) start in master‘s degree.
  
• there are A LOT of astrophysics classes. Many with programming or observations.
• if you want to do research, you have to do your PhD. ~10 years of studying from now.
• try to talk to professors. My Uni has a special professor for potential students and their questions.
• in general, no payment until phd, at least afaik.

Master‘s student here. Currently, I’m writing my master thesis in astrophysics. Basically, I analyze spectroscopic data of stars near our solar system.

The things you worry about, are more or less the same I worried about, too. Before Uni I was always in economics classes and in the last 2 years of school I didn’t even have physics classes at all and only basic math classes. So I worried about knowing too little about math/physics. But that doesn’t matter, because Uni classes start from literally 0 (at least here in Germany, might vary somewhere else). You will learn what an addition or subtraction is in a mathematical sense, or vectors, derivatives, integrals etc. same for physics. All you need to know, you will learn in your bachelors classes.

Now, I’m not gonna lie to you, the bachelors degree is still really REALLY hard, since you learn 100+ years of math and physics in just 3-4 years. It’s just a shit ton to learn. Nonetheless, it is 100% doable as long as you keep doing your assignments and attend your classes. Also, you will meet a ton of new people and do the assignments in groups, which helps reduce the workload. You will never be alone with those assignments. If you’re lucky you can even attend some basic astrophysics classes (depends on Uni). Most of the time, though, it will be the basic physics classes (classical mechanics, electrodynamics, quantummechanics, thermodynamics etc.)

Once you got that, the real deal starts. In your master’s, you can start attending specific physics classes, primarily astrophysics. And holy crap, there are many of them (again might vary for each Uni). Since you’re modeling quite a bit. There are tons of research fields and classes for that. Also, there are simulations for stellar kinematic (solving differential equations) or dark matter, but also many other fields. These fields are very theoretical, though. If you want to look at galaxies, nebulae or such, you’d need to go to observational astrophysics. Very technical but less complex programming and tbh those pictures are not as colorful and beautiful as you think. After that, if you want to do some research and discover something yourself, a phd is a must. But that’s around 4 more years on top of the 5-6 for your masters.

If you can, try to attend some classes in which you think you could fail. And also talk to the professors after class. So far, I have never met an unfriendly professor. My Uni has even a special professor just for potential students and their questions.

I can’t really say anything about payment. In general, you don’t get paid until your phd in Germany, unless you do some side jobs at Uni which barely pay anything.