This thread should have gone in the General Chat section. I'm sure one of the mods will move it there for you. They stick the General Chat section at the very bottom of the forum's main page. It's the 3rd one from the end and most people don't look that far down.
--------------------
You don't need a college degree to run a business but you do need to do a small business course so you know how to do the book keeping, taxes and other things associated with running a business. You can do small business courses full time during the day, or part time in the evening. There might even be courses available online.
Having said this, don't bother doing a business course when you leave school. Get a proper job (apprenticeship) and get a trade qualification in one of the major fields, mechanic, plumber, builder, baker, electrician, etc. This will give you an income and a profession to use before you buy/ open your business. And if the business fails (lots do), then you will have a profession to fall back onto.
You can study small business courses while you are working as a professional tradie, and buy a house, car and get some savings in the bank. Then go and work in the pet industry part or full time for a few years and see how you like it. Even if you do volunteer work at a pet shop on weekends, it will let you see what happens and how it works. During the week you can do your normal trade/ profession.
----------------------
If you do open your own pet shop, try to find an area where there isn't a pet shop within 5-10km. Look for an area with a lot of families living nearby, and locate your business on the edge of suburbia and a light commercial district.
Rent is generally cheaper in industrial areas but you want to avoid heavy industrial areas due to the pollution and noise. A light commercial/ industrial area has cleaner air, a cleaner environment and cheap rent.
If you set up a business in a shopping centre or the middle of suburbia, you will pay top dollar for rent and waste all your profits paying some scumbag landlord. An example of this is one of the shops I worked at. It had been in the same location for nearly 20 years and was originally classified as a commercial district. Over time the surrounding area was developed and turned into housing. The owner of the block of units decided he was going to raise everyone's rent because it was now residential instead of commercial. However, instead of increasing rent a small amount like you normally do, he got greedy and decided to increase the rent from $3000 a week to $20,000 a week. Subsequently 90% of the businesses closed and either went elsewhere or just shut their doors for good. Several years later, most of these building were still vacant and it wasn't until he dropped the rent before anyone moved into them. The businesses simply could not take that sort of increase in rent.
You try to have your business near a suburban neighbourhood so you attract families who come and buy furry, scaled or insect pets or fish. If you are too far away from suburbia, people won't know you exist and you will need to do a lot more advertising and have a limited number of customers. People don't want to travel miles to look at the puppies, birds and fish.
--------------------
Unless you run the veterinary clinic, there is no reason to locate your pet shop next to one. A drawback to having a pet shop near a vet is diseases from the animals at the vet can be transmitted to the shop animals more easily. You will have enough diseases in the pet shop and don't need more coming from a vet clinic. You can have your pet shop in the same complex (group of units) as a vet, but I would try to keep a little distance away from a vet. Likewise I wouldn't live or set up a business near a hospital, petrol station, school, or major shopping centre. These locations regularly have a higher crime rate or more pollution. Hospitals have sick people that you don't want near your animals.