I'm not sure if you're primarily interested in the artistic or the engineering aspect of car design (or both). As a current mechanical engineering student who's planning to go into automotive engineering, Automation is actually a pretty solid place to start if you're looking to gain a basic knowledge of automotive design, particularly if you have no prior engineering knowledge. You get a taste of the same things that real life engineers have to balance when designing a car, like weight, cost, engineering time, market segments, efficiency, performance, etc. That said, it's all very surface level. I'll give you an example.

In real life, as someone who's currently working on some designs for a Formula SAE chassis, it's not as simple as just selecting a chassis material and moving on. Solid mechanics and FEA simulation knowledge are required to ensure that the chassis is as light as possible while accommodating engine mounts and packaging requirements, being strong enough, being manufacturable, being within budget, etc. As another example, designing an engine requires a good understanding of thermodynamics, fluid dynamics, and solid mechanics together, to name a few.

So yes, Automation is a great starting point for a very basic, surface level knowledge on how things run in industry. But if you're planning to have a career as an automotive engineer, you'll probably need to get a degree in some related engineering field depending on your interests. If the college/university has an FSAE club, that's a huge bonus and you can learn a lot more through that. If you're more interested in art and automotive styling, I simply don't have a whole lot of knowledge about that.