For actual advice, you haven't offered me enough information to be of use.
Is there some reason you need to be so circumspect? Folks would probably be able to give you better feedback if they knew more details about your choices. Is it between taking holy orders and joining the army? Termination of a pregnancy or carrying a child to term? Dating a boy your folks don't like or leading a celibate life forever? Becoming a Muslim or an atheist? Devoting your life to tennis or nuclear physics?
Outside advice will vary depending on the conflict and those you ask about it.
One way of helping you might find useful is by making the parts of each choice more and more specific. Since the conflict of Tennis or nuclear Physics is probably highly unlikely, it might be a useful example. You start out by taking one of the two choices and stating it in a sentence:
"I want to devote my life to tennis."
Having gotten this basic description of one part of your choice out, the idea is to make that sentence as fully specific as you can possibly make it. The more completely you can specify the details, the clearer the decision will be to you after you run through the process with the nuclear physics half, later on. So, you ask yourself, what do you mean, exactly, when you say "devote your life to tennis?" Could you make that part of the sentence more explicit, please?
" I want to spend the next 20 years of my life playing tennis."
On what level, specifically, do you want to play tennis for the next 20 years?
"I want to spend the next 20 years of my life playing professional tennis."
With whom, specifically, will you play professional tennis over the next 20 years of your life?
"I want to spend the next 20 years of my life playing professional tennis with professional tennis players."
And what, specifically, will you have to do to play tennis with professional tennis players for the next 20 years of your life?"
"I will have to practice seven hours a day, seven days a week, reach a professional level of play myself, and be able to win enough money on the circuit to support myself for that period of time, be able to save enough money to have money for retirement, and make decisions about relationships and children that I find I am comfortable with over that period of time and later so I may play tennis for the next twenty years of my life."
I can stop there, feeling I have given a decent example of what I mean. If you can go through this process with both sides of your conflict, the odds are that the conflict will tend to clarify itself and one side or the other will begin to look like the better course of action. The idea is simply to get each side as fully specified as you possibly can. The premise is that these things look as though they are in conflict because they haven't been examined as fully as they need to be, and once you do this the solution will emerge naturally.
Lacking a description of the problem, it's the best I can offer you right now. I hope it's of some use.
Sincerely, Bob Kaven