When I was a teen and facing a difficult decision or major life change, I used to ponder the impossibility of following a "straight and narrow" path based on the advice of others. Think of all the phrases people use to sum up the "moral of the story." What do friends and family members advise in tough or turbulent times, such as a messy divorce, life-threatening illness, transition from one phase of life to another? The answer is: there is never just one answer. People can give inherently opposite yet equally reasonable-sounding advice for the same situation.
For a simplistic example, observe the contradictions:
absence makes the heart grow fonder/
it's better to be happy in a cardboard box than to be alone in a castle
don't judge a book by its cover/ a first impression is a lasting impression
where there's a will, there's a way/ let it be and move on
a penny saved is a penny gained/ you were born nto this world with nothing, and that's the way you'll leave it
don't put all your eggs in one basket/ have the courage to take a risk
two heads are better than one/ too many cooks spoil the broth
I'll bet you can think of a lot more. Now that I am a little older, I understand that circumstances play into these and other phrases of conventional wisdom. "It depends" seems to be the ultimate answer. However, on some level, we all need a foundational belief that transcends the subtleties of any individual situation. It's a lot like religion, in my opinion. It's important to have an open mind, and to make the effort to understand and respect the differences in theology, but if that's all you do-- if you spend your life surveying and dipping into the value systems of others-- then you won't have the chance to live by your own.
There is a delicate balance between an open mind and a made-up one. My hope is that you can learn to cultivate both. Some people seem to know what they're about, why they're here on this earth, and exactly how they plan to live their life; they've got a style and they stick with it. If you are anything like me, you'll be so in tune with the gray areas of life, that it will be a challenge to find your own black and white. I hope that you aren't as susceptible as I am to the magnetic pull of others. The power of persuasion can gain your allegiance to any side of any coin, if you allow it. Everyone will have advice for you at some point in time, including me, but in the end, you will be held accountable for your own thoughts and your own actions. God didn't make us to be his puppets; he left us to make our choices and to grapple with our will. It's a challenging blessing, but one that you are equipped to handle. Take it from me... with a grain of salt, of course.