I'm 16 and want to start building my credt?
Why? Your credit score is based on how you pay off cards and loans. You are far too young to get either, so you won't get a credit score until you are of age.
Not possible at age 16.
At 16, you are too young for credit. You need to be 18 years old. At 18 you can start building credit. At present you are still a minor. Credit is a personal thing anyway, you can't build it, or have it destroyed, via another person.
What you can do at this age is start forming good financial habits that will lead to good credit, later. Sounds like you're a forward-thinking person, so can understand the importance of getting fundamentals right. Many of the questions here involving credit trouble have stories about making foolish choices when first starting out. Either of your parents can open an account in trust for you at a bank, then get a debit card attached to that account for you. I don't that that overdraft "protection" can be put on such an account, but if it is offered, decline it. Ideally, the account should be funded only with money you personally earn (an allowance counts, if you do chores). I'd recommend against either of your parents listing you as an authorized user on their card. When someone else is paying the bills, the money management lessons are not nearly as good. This is a USA answer. If you are in the UK or elsewhere, let us know.
You may be able to get a discover secured card now on your own. Or get a joint credit card with a parent. Note. being an authorized user is NOT the same and does not build credit. However, waiting until you are 18 would be fine too. It's not like you will be borrowing much without a good full time job anyway.