Questions on starting a business as a minor

I'm seventeen right now and have a few ideas for businesses I would like to get into, but I'm not sure about what issues I'll encounter due to being under 18. Can I register an LLC (I'm in Illinois if that helps)? Is there a way for me to obtain a business credit card, or will I have to do everything through someone who is over 18? Are there any other legal issues that I will run into due to age?