well, i think you're right to put more respondsibility to your work
because you will be a leader in the future after a marriage and you might plan to collect money enough for the expense.
But you think about yourself, Don't you put more time to do it?
and if she understands what you're doing, it's for you both, not only for youself. Then she will be okay if she totally understands you.
Umm, she's in college , i think she shoud know what is the life after graduate.

So try to explain to make her understand.