I am 17 years old and I intend to study computer science next year in a university which is mixed (boys and girls). Is it permissible for me to study in this university? I will cover my face and will strictly abide by the rules of the Islamic Sharia. If it is not permissible please let me know why. Also, in my country there are very few separate universities for girls and boys, so I will have to study in a mixed environment; .I don't want to remain uneducated.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

Basically a woman should stay in her house to keep away from being mixed with men.
If there is no one who sponsors her and she needs to work to get her necessities, and getting work requires a degree or diplomas, then it is permissible for her to study in a mixed university provided there is no alternate for her.
On the other hand, if she has to study in a university she has to meet the following conditions.
1. Her presence is limited to attending lectures only.
2. She has to wear complete Hijab. She should not put any perfume nor expose her adornment while she is out of her house.
3. She should avoid sitting next to gents.
4. Talking to men should be limited to the minimum necessary. Moreover, her speech should not be too complaisant and should not contain any matter that is shameful or might cause temptation.
Allah knows best.