My 2 cents:
Seek first God and his truths. Find out who He is and who Jesus is and follow their teachings of wisdom.
Once you have become a Christian, you are 'newborn' with a new Christian heart of love and compassion.
Now, life's journey is ahead of you. Yes, God has the desire and the plan to prosper you and to make you grow. And God may use you to help others along the journies of life. But what you want to do in life is up to you. As many people here have said, your life is your choice.
When people get pets, like a hamster or a dog, sometimes they just sit and watch to see what their pet will do. And sometimes they do the silliest things, and other times, the most wonderful, loving things.
God is not much different. He created us, but He doeesn't force us to do this or to do that. He watches us, waits for us to seek Him, and blesses us. He will allow us to also choose our own paths in life. You want to be in computers, God can help you. You want to minister in far away lands? God can help you. You want to just have a quiet life and have a Godly family, God can bless you there too. And this has been shown in the bible.
There was an Israel king who was about to die, but he asked for an extention to his life. God gave that to him. The Israelites, after living in the promised land for a while, asked God for a king (they had none at the time), and even though God knew it wasn't the best for them, he gave them one.
God loves all his creation, especially those who love him back. And he lets each of us choose our path in life.
So if God lets us choose our paths, then which is the right one?
Look at your heart and see what you want to do. Look at your interests and your talents, combine, and succeed.
But what's the purpose of life? Solomon covers this in the book Ecclesiastes. For the most part, life is meaningless. You can spend your life to gain wealth and possessions, but when you die, all that will just go elsewhere. Solomon, the wisest king in the history of Israel, decided that the purpose of life was simply to enjoy the fruit of your labors. Work your job with satisfaction, and enjoy the results of your work.
That's what makes life meaningful. Not to satisfy pleasures. Not to accumulate wealth. Not to try and life in luxary. But just to seek God, work and pay your dues in whatever field you strive for, and to enjoy the fruit of your labor.
So first, seek God and seek Jesus so that you may be blessed with whatever you desire to do. Then, seek what is in your heart: computers, medical, helping others, the armed services. Then spend your effort doing that and trust in God to guide you, open doors for you, and richly bless you.