She is studying in a place where evil behaviour is widespread among the students
Question

I am very confused and in need of your help. I am a student in a private course of teaching in a centre. When I started my study there I saw strange things being done by students. Very tight, short clothes, skirts opened till thighs, shoulders and breasts shown, even backs are uncovered. If you look at their eyebrows you find them plucked or dyed to blonde colour. Even the manager of the centre, she wears shorts clothes and plucks her eyebrows. I do not know how to denounce this munkar; they are very huge number, about 400. I asked some religious sister who advised me to leave the place, as she knows them and tried before with them but they did not respond. They did not even let her teach the cleaners about Islam.
  I am very confused now. I do not know what to do. My family will not accept this matter of leaving this study. I will also feel failure because I could not join a university. Although it was due to my wish, the speciality that I thought will achieve my ambitious was not available in my area. Everyone will think that I am a failed individual, although I love seeking knowledge, I just did not have the chance. If I leave this course now everyone will believe I am a failure.
Praise be to Allah.We think that you should carry on with your studies, and advise others as much as you can, and call people to Allaah with wisdom and beautiful preaching. That may done by speaking to your colleagues, explaining the ruling on plucking eyebrows and the duty to cover the ‘awrah, and the definition of what it is and is not permissible to uncover. It may not be possible for you to speak to all of them, but try your hardest, and do whatever you can. Seek the help of useful means such as giving them pamphlets and telling them about websites or useful lectures. You should cooperate with other righteous women among your colleagues to create a positive atmosphere for da’wah and to influence those around you. 
As for despairing that things will ever change, this is not the attitude of the daa’iyah, and it is not supported by reality. How many universities were filled with mixing and evil that were greater than what you have described, but da’wah was successful there and bore its fruits, by the grace of Allaah and due to the efforts of the righteous and patient daa’iyahs. 
We see the efforts of those who want to spread corruption and confuse people and distort sound human nature, even though they are working in a society that is conservative and hold values that are diametrically opposed to their values, but nevertheless they do not despair and they never say that their plans have failed until they try. Those who seek goodness should be striving harder and being more patient, whilst seeking reward from Allaah, because they are bearers of the truth and spreading goodness, and they have a higher aim and a more sublime message. Moreover, they are working within a conservative environment. All the daa’iyah has to do is to stir people’s hearts and awaken their innate love for Allaah and love for His Messenger (peace and blessings of Allaah be upon him), and he will see the effects of that sooner rather than later.
We ask Allaah to help and guide you and us. 
And Allaah knows best.