Start at a dealership and learn all you can about one brand of vehicle. Later, once you save enough money to open your own shop, specialize in that make. The independent shops that service all makes and models are a dying breed. Costs too much to keep up with all the training for all the brands and to buy all the special tools and equipment.

You wont have enough money or experience probably to open one. Keep working until you learn the business side of it as well as completely being able to rely on yourself for taking apart cars. If your good and fast though you might actually be able to make more money flat rate unless your shop does really really well. By the time you have money to own a shop you may not even care to own one cuz you will have so much already.

Don't know where you are, which country, etc.

Learn at a tech school, community college, etc. Then get a job at an established garage, dealer, etc.

You aren't going to get any business if you go off on your own as nobody is going to trust a kid with their car.

Starting your own garage is a big undertaking, unless you happen to have a very good rep around town to start with. Probably best to start at a local garage & put in some time learning the ropes. One of the bigger killers of a small garage is the paperwork needed to keep it going. So, if you are single, start dating a fledgling accountant.

Chances are if you are just learning about cars and only do basic work on them you don't have $50,000 to buy equipment to open your own repair facility. Then there;s also the fact you need another 10 years of experience! Working at a dealer is not very much fun. I've spent many days standing around 8 hours with no work. You don't get paid unless you turn in work completed. Flat rate sucks. The only benefit of working at a dealer is factory training.

To open a shop, you have to be a businessman more than atechnitian. Yes, you can do both, but you need training in both fields. With your own shop, you are likely to spend more time running the shop than working on cars, With a very successful shop, you will have technitians working for your business.

I suggest you get your papers, work at a dealership, and watch for the problems in running it. There is money to be made (or lost) with your own shop, and you may or may not prefer to take the step

I like Ford, Toyota, Honda, Porsche.

I'm a senior high school student making a mind if its better to work at a dealership or open up own auto shop?

I'm aware that most dealerships uses flat rate system and I do have some knowledge about cars in general.

I work at a private auto shop as of currently.

Oil change, mount and balance tire, brake fluid, transmission fluid, brake pad and rotors replacement. ETC. I pretty much do the basics stuff.