Is it permissible for me to travel to one of the Western countries to complete my studies, knowing that I fear this might be considered a contradiction to what I used to advise people against, regarding traveling there? And does this fall under the category of: "I used to enjoin you to do good, but I myself did not do it"?

The answer can be summarized as follows: Studying in disbelieving countries is not permissible except out of necessity, such as the unavailability of the required specialization in Muslim countries, provided that the student possesses sufficient knowledge to repel doubts and steadfastness to ward off desires, as stated by the Permanent Committee, Ibn Baz, and Ibn Uthaymeen.

As for your previous enjoining of good and forbidding of evil despite your own transgression, this is a grave error. The Messenger of Allah (peace be upon him) warned against those who enjoin good but do not practice it, and forbid evil but commit it. A Muslim should ensure their words align with their actions. However, this does not mean abandoning the enjoining of good and forbidding of evil. Rather, what is required is for a person to strive to reform themselves while persistently enjoining and forbidding with sincerity and devotion. Al-Qurtubi, Al-Saadi, and Ibn Kathir mentioned that the reproof in the verses related to this is due to abandoning good deeds, not due to enjoining them, and that a scholar should enjoin good even if they do not practice it.