Must I wear the hijab again upon my return, knowing that I do not wish to wear it now, but I plan to wear it in university in the future?

If a girl reaches puberty, she is not permitted to delay wearing the hijab, because it is an established obligation. If she has not yet reached puberty, her family should accustom her to modesty and covering. This becomes even more critical if she reaches a stage of maturity where she attracts men; in such a case, her family must compel her to wear the hijab, even if she is young. Therefore, displaying oneself immodestly (tabarruj) and abandoning the hijab are major sins, and one must hasten to wear it in obedience to Allah. If you are not convinced about delaying it, then this is correct. However, if you are not convinced about wearing it before university, then this conviction is false. The duty is to obey Allah's command and His law, and the hijab is obligatory in every situation as long as the woman is in a place where she can be seen by men who are not her husband or a mahram.