Being a full-time student has no actual direct bearing on your taxable income or your refund. It can affect the amount of your standard deduction when you are eligible to be claimed as a dependent of another taxpayer (as the vast majority of 19-year-old full-time students will be), but it doesn't affect your refund.
Your refund is a function of the total (and type) of income and the amount of tax that is withheld.
It sounds like you aren't quite finished with your return if you are still being asked questions about deductions. You need to answer those, just the same as a full-time employed taxpayer would. It could result in additional funds being added to your refund.
If you aren't receiving the majority of your federal withholding back, then you made enough income to owe some federal tax. If you are looking at your social security and medicare taxes and considering those in your calculations, those are never considered as part of refund calculation.
