Welcome to the world of diabetes, diabetic1. Of course it's not exactly the club you wanted to join, but it beats a lot of them.
The first thing you need to do is ask your doctor what education facilities are available in your area. There are various courses you can go on, and if none are available, you should have access to a specialist diabetes nurse who can advise you on everything and unravel the mysteries.
The most important thing you will need to learn is how to work out how much insulin to have to balance the carbohydrate (starchy foods like bread, potato, pasta etc) that you eat. It is done on the basis of working out a ratio of insulin to carbs and that ratio is different for everyone. It is often different between morning and night for the same person.
Remember that physical activity will lower your blood sugar, sweet foods like sweets etc, will raise it quickly and can start off a bit of a roller coaster of ups and downs if you're not careful. Sweet foods are not a no no at all, you just need to learn how to balance them with the right amount of insulin, and, just like the rest of the world, it's not too healthy to have too much of them. There's not much in the food line that you really shouldn't touch, but non-diet fizzy drinks is one I never go for because they are soooo sweet and will kick your blood sugar (BS) sky high, so reserve such things for if you go hypo - and you will sometimes, it's inevitable.
I was diagnosed at age 17, about 35 years ago, and I still remember the attitudes of other people. I don't think much has changed in the public perception. People will try to tell you that you shouldn't eat anything with sugar in it: don't listen to them, just learn to balance insulin and carbs and you will be fine. Sometimes you will go hypo and sometimes your BS will go high: these are absolutely inevitable, no matter how hard you try to keep balanced it is a bit like keeping both ends of a seesaw off the ground with a wobbly weight jumping about in the middle, pushing one end down then the other. Controlling what that weight does will take time to learn. The weight represents the variables like emotion that often pushes BS up due to adrenalin whose job it is to fill your system with sugar so you can run or fight: it's a pain for diabetes and you can't predict when it might happen. When it feels as if people expect you to have perfect control, ignore them if you can. All you can do is your best and as you get to know how your body responds to insulin your control will get better and better until it all seems easy. But even then, don't expect perfection, you will only be disappointed: it's ok to not be perfect, none of us are.
With that in mind, you MUST make sure that you keep some fast acting carbs with you at all times. Preferably a drink, a carton of fruit juice is good although a bit bulky, because liquid is absorbed into the system much quicker than solids are and when you go hypo you need to treat it is fast as possible because then it doesn't go so low that it leaves you feeling like you've been run over by a truck. That must up there is about the only must to remember... except of course the obvious of don't forget to have your insulin and balance it with carbs.
One of the biggest pains of the whole thing is that you cannot just say, 'Hey let's go out for bit,' without making sure you have your emergency rations with you, and if you are not going to be back for a bit, you have to take your insulin too. It seems like a little thing, but it is the one thing I sometimes resent even now, that I have to make sure I have that emergency kit with me. You get used to it and life goes on and you can live normally.
I have spent my life working with horses and bringing up children that I had normally and none of them have diabetes. I have done and still do endurance riding which is quite a challenge, but worth it and I am now training to be a driving instructor, which is no longer a banned profession. There are still a few careers you are not allowed to go into, but they are not many.
I hope you manage well. There is loads of advice and support available in these pages, and if you insist, and I mean insist because you might have to, on getting some comprehensive education about how to manage it all then you will do fine.