For some perspective: your computer skills/knowledge sound pretty average, not lacking. They may be short what you need to get to where you want to be, but keep in mind that means that where you want to be is a fair bit above average.
When people ask "well what do you want to create/learn" that sounds like it may relate to what you've talked about. For example you want to learn music recording. Presumably, that's because you want to make music, either your own or to work on that aspect of music making in collaboration with a performer. CAD is more vague because it's super flexible -- compare to learning to paint, that can mean anything from a delicate oil still life to house painting. Those questions are usually looking for a specific example of a thing to make so that the person responding can reduce the problem down to a series of steps. Let's say you want to CAD a chess set: the steps are probably something like
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get a CAD program like Autodesk Fusion 360 (free and a good place to start)
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follow a tutorial that involves making stuff that is cylindrically symmetric (I really like this tutorial
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Try doing it yourself by making some simple chess pieces, paying attention to dimensions to ensure you're making stuff that is a reasonable size
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Post your designs on Thingiverse and/or on a 3d printing subreddit to see if someone can give some feedback/a test print
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Document the whole process and throw it in a blog post, now it's part of something you can reference in your resume
So let's say you do this. Does this mean you've now learned all CAD? Nope, there's a ton of stuff left to go. You can use CAD for designing stuff with mechanical parts and motion; you can use it to test stuff like stress and airflow and more. But this is a place to start. Ideally, what happens in the process is that you get more familiar with CAD in general and the software you're using in particular, and you join a CAD subreddit or something, and you see a lot of other possibilities that are out there, and that helps you get other ideas of things you want to do. So the idea behind "what do you want to do" is just to turn desire into an actionable process with a clear starting point, whose outcome is usually a completed product of some sort, rather than a completed unit of learning.
That's a great way to learn, but it's not the only way. Check out stuff on coursera, edx, and other online learning platforms designed around offering free classes like this CAD class (don't know if it's any good, just an example). When I wanted to learn Python (a common programming language) I didn't really know what I wanted to make with it, so I went through one of these classes, and it gave me a chance to get familiar enough that later on when projects presented themselves I could just hop in and do them. You don't have to know everything that's possible to do with a particular tool in order to decide something to do with that tool, but sometimes it helps to just have some guided fiddling around time in order to get the skills and confidence to connect the tool to an accessible application, and that's what these classes can be good for.
I love job postings that look interesting and list tools (software, languages, processes etc) that I haven't used because it gives me a checklist of things I'm likely to need to know to do that job. I add those to a running list of stuff to learn. For software I look for free/open source versions, and keep in mind that some employers may not consider that sufficiently equivalent, but not all. Again with the CAD example, many employers want people to know Solidworks. But that's a pretty expensive piece of software and most private individuals don't use it. Most employers needing CAD will prefer Fusion 360 experience over no CAD experience at all, so it's worth applying, but if you find that Solidworks (or whatever software) is critical to getting the job you want, check out community college options. A lot of software offers cheaper academic licenses, so for the cost of the software itself or even less, you can get a class on the software with a temporary license to use it.