The basic principle is that it is not permissible for anyone to study in mixed schools, because of the evils and haraam things that result from mixing, as is obvious to everyone.
If there is an urgent or genuine need to study, and there is no option other than mixed schools, then there is nothing wrong with you completing your studies, but you must lower your gaze and avoid the causes of fitnah (temptation), and remember that Allaah is always watching you, in secret and in the open.
Shaykh Ibn Jibreen (may Allaah preserve him) said concerning the one who is faced with this problem of mixed schools: They have to try hard to lower their gaze, protect themselves and keep away from temptation which could lead them into haraam actions. If he notices that he is starting to slip towards something haraam, he should stop attending. End quote from the answer to question no. 6118.
We ask Allaah to make you steadfast in word and deed.
And Allaah knows best.