Max,
An Automotive engineer is usually a Mechanical Engineer of some type, who later attended a specific course to complement his/her education. Many Industrial designers also become Automotive Engineers or work close to mechanical engineers designing both cars and motorbikes.
Engineering in general is exciting, taking something from concept, to prototype to functional component/assembly is very satisfying.
There are Marine Engineers, who design boats and ships. There are Aeronautical Engineers that design things that fly. In any Engineering field apart from civil you can pretty much chose what you want to specialize in with additional studies/experience.
Money you earn, could be anything from below average (for 4-5 years, maybe more or less..) to massive salary. Depends if you work for your self or a large multi national company. You need to establish your self as a quality engineer either way, many companies will promote within their ranks, and send some one to get further qualifications with a increased salary.
An engineer needs to work within constraints, what i mean is you are given a budget, a work envelope, a material, a function, or any combination of these and other constraints. A good engineer will feel most comfortable under this sort of work load (some call it stress), engineers call it work load....LOL... So designing cars is based on the limitations and guide lines and your ability to be within these. All you are doing is following a set of rules that have bee formulated since the first motor car rolled off the production floor, and many by experience and experiment. In this day and age it is an exacting science, and your tolerance is much smaller, by the same token you have many tools to make your job more exacting. The exceptional engineers are the ones who innovate, the rest follow, if you are good at one or the other you are a great engineer. As these days the word engineers is throw around allot by anyone who fixes things?!?!?! Engineering is about solutions.
Engineering is like Medicine, you have to keep up to date or you will lag behind.
This is a bit off topic but it may be helpful.
Don't rush into anything. Some of the best motor sport/automotive engineers started off as mechanics, and studied along the way. Mechanical engineering is a diverse field, most important is to research the backgrounds of the Engineering Faculty at the university. It will give you a good idea of where to attend, as the people who tech you will have some bearing on how you apply your knowledge. Also you can use any mechanical engineering degree as a stepping stone to a more specialized field. Also Mechatronics/Robotics Degrees a great. Many Automotive specific degrees will take 2nd-3rd year students from other universities who show great interest and potential. This way you also will get the fundamental skills required in all engineering fields. From my experience, don't be in too much of a rush.
Hope this information helps. Make engineering a hobby, and you will never work a day in your life.
