Is fasting appropriate for this situation?

Because you have already decided for just two options, it does not have much meaning to want God to choose one of them for you.

As you decided for yourself that you want to do just these two things, so also you should decide for yourself which one you want to do more.

If God wants something different for you, it will happen, anyway.

I have found fasting to be useful only insofar as hunger pangs are reminder to be in prayer for whatever it is that I am praying for.

God is able to use whatever path you choose. I would suggest contacting several people in each field and ask them if they could give you descriptions of what the daily work is acutally like. This may help you make a decision.

Fasting and prayer has worked for me.

What I would do in a situation like this, if I really needed an answer, is: fast and pray God lead me into the right path, and then do research into which field would be better suited long-term as a career.

Questions I would be asking myself would be things like:

• Which one would allow me to still serve Him best?
• Which one would allow me to serve others best?
• Would one of these careers compromise my faith: i.e, would I have to work on the Sabbath? Will I get Holy Days off?
• Who would I be working with and what will the environment be like? i.e, low-stress; high-stress; combative; peaceful; godly; ungodly?
• Is there demand for this career? Will there be greater demand for this career in the future?
• Am I physically or cognitively capable of this job?
• How many hours will be expected of me? Will those hours interfere with church or family?
• Would I have to move/relocate to find a job? Would I be willing to move/relocate if need be?
  

If you're interested in medical. Figure out if that's being a doctor, a nurse, a technician, phlebotomist, an aide, a medical biller etc. How far are you willing to go? What aspect of medical interests you? Likewise list out what you would like to do with a computer science degree.

God can help you rationalize your decision through prayer and fasting.

Fasting always adds strength to prayer.