Do I have to be 18 to do my own taxes?

No you do not have to be 18.  You do have to be 16 by the end of 2019 in order to e-file.  If you are a teenager you are a qualified child for your parents--so in My Info you need to say that you can be claimed as a dependent on someone else's tax return.  This is important--do not mess it up.

CAN I FILE A RETURN IF I AM A DEPENDENT?

If you can be claimed as a dependent on your parents’ return, you can still file your own return so that you can receive a refund of taxes withheld.  (You will not get back anything for Social Security or Medicare withheld.) Be sure that on your own return you say that you can be claimed as a dependent on someone else’s return.