There is that age old saying, "if you want something done right, do it yourself." If people wait for someone to make their decisions for them, then they are going to be waiting along time. I always make my own decisions because once you fall on hard times, no one is going to be there to help you, except you.
Personally, I feel people should learn how to make decisions for themselves early on in life. However, I feel important decisions should take into account two factors. First, it's important to have people whose opinions you know and trust and can consult. Second, it's good to consult additionally with facts, and weigh the pros and cons of any option. So while the final decision should be up to you, it should be one that is a well-educated decision.
I have no doubt in my mind that I make all of my own decisions when it comes to important decisions. I have lived long enough to know that at the end of the day, you have to do what is right for you. I do however let others sometimes decide what's for lunch.
I make important decisions for myself, because I am the one who has to live with the decision. I also know myself the best, so I have the most information available to me to make the decision. Other people might not have your best interests in mind, or they might not understand the reasons for your decision.
I like to be the one in my life who makes any big time decisions, so that I can think through both sides, and so that I can make sure that I make the right decision and that I do not do something that will come back on me later.