Is it permissible to postpone marriage for worldly matters, and is it permissible for parents to complicate marriage based on worldly specifications, knowing that the suitor is religiously committed and financially capable, and that he fears temptation for himself?

Your parents are not permitted to object to your marriage on the grounds of waiting for the completion of studies or similar reasons. Rather, we advise you to hasten to it as long as you are able, especially when there is a fear of fitna (temptation/strife). Similarly, they are not permitted to object to your marriage to a girl of good character and religious commitment under the pretext of social or financial differences, for the criterion is piety (taqwa). However, if one of your parents objects to marrying a specific girl, and you fail to convince them, then you must leave her and seek another, because obedience to parents takes precedence over marrying a specific woman.