A lot of what i'm going to tell you is very much my own opinion and not necissarily the way everyon in the lifestyle operates. Every person is different, so it makes sense that ever D/s relationship will be different, dependant upon the wants and needs of those involved. So now that i've got my disclaimer out of the way, here it goes.
Being a sub is all about having your own rights and choices. You choose to submit and you have the right to set any limits you feel necissary and to bring up any concerns you may have with your dominant. Being a sub is not about being a mindless drone that does whatever a Dom tells them to do. It's about trusting your Dom to know what is right for you and help you make decisions and guide you in all that you do.
Trust is a hugely important part, and i think some of your retisance is stemming from your trust issues. *just speculating here, i don't mean to offend* you may not be able to imagine what it is like to trust someone else so fully that you know they will be able to make the right decisions for you and guide you in becoming a better person and sub, so that may be why you feel as though you'd be losing your rights and ability to make choices while submitting.
i believe that being a submissive is the best way to grow as a person, not a hinderance to it. Through the guidance of your Dom you should be able to grow as a person, to do everything you've dreamed of. Your Dom should be there to help you through new obstacles, not hinder you from taking on new chances and opportunities.
All that being said, you can always tell your Dom that a certain part of your life is strictly under your power. Such as, career, where you live, etc, etc. In this instance you would make the decisions for yourself, rather than deferring to the wishes of your Dom.
And just one more disclaimer: This is written in the ideal of an understanding and reasonable Dom, not someone who is just out to totally take over and manipulate another's life. There are always risks when entering a relationship like this, however, you always and i stress, always have the right to say no.