I am a 18 year old student and am best friends with a girl of the Muslim faith.She is a penfriend and over the years has told me much about her religion and her customs.Though I am not Muslim, I am very interested in the concept of hijab, not just as items of clothing but also because I believe in modesty and respect for all women. I know from her that Muslim women should not dress like non-believers but I ask, is it okay for a non-believer to dress Islamically ,as long as it is out of respect and admiration and seeking modesty? Would this offend Muslims, since I am not Muslim myself? I respectfully ask for your guidance.

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.

Legislating Hijab for women to wear, is one of the Merits of Islam. One of the most important objectives of legislating the Hijab is to protect the woman. Also, Hijab is a matter that corresponds with the Fitrah (natural disposition upon which Allaah created mankind). Since you are interested and impressed with the concept of Hijab, then this is a good characteristic in you and it is evidence that your Fitrah is sound and that you have a sound mind, which we hope will guide you to the ultimate goodness of embracing Islam. Islam is the true and final religion by which Allaah abrogated all previous religions, and Allaah does not accept any other religion but Islam.

Therefore, we advise you to embrace Islam so that you will become happy in this world and in the Hereafter. The following are some Fataawa (plural of Fatwa) which will help you in this regard: 81979, 86091, 88906 and 88627.

As regards your wearing the Hijab, then this is permissible and this neither causes any harm to the Muslims nor hurt their feelings. 

Allaah Knows best.