Should a young man inquire about a girl he finds suitable for marriage while he is still studying, or should he wait until he is ready to propose to her?

You are not required to ask about the aforementioned girl, nor to inquire about her religious commitment and character. As long as you are currently unable to marry, it is more appropriate for you to turn away from her and occupy yourself with what benefits you in your religious and worldly affairs. When you become capable of marriage, then propose to one whose religious commitment and character you approve of. Be diligent in lowering your gaze and closing the doors to temptation in the mixed-gender university environment.