There are some careers that have rules or restrictions on hiring Type 1 diabetics, such as pilots, fire, police, military and jobs that involve driving. If you are interested in one of these careers you would have to speak to a school counselor and find out specific restrictions.
Aside from that, you can do absolutely anything with Type 1 diabetes that you could do if you didn't have it! The only thing you can't do is ignore your diabetes. If you learn how to manage and control your diabetes with regular testing, shots (or a pump), matching doses to carbs, correcting highs, etc you can fit these things into your life very well. It isn't easy, but Type 1 diabetics live happy busy lives, have children, are athletes, etc. We even have one of our own on American Idol: Crystal Bowersox is a Type 1 diabetic who is on another board I frequent! So don't even think you can't do what other kids and adults do because of your diabetes! Just work on learning how to control it to allow you to live the life you want!