I am studying in Japan in one of its universities. As there is no place for prayer, I pray while I am sitting in my desk. Being in a non-Muslim country, I don't like to pray in the garden to avoid having a problem with bad people. Do you think I made the right decision?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Al-Qiyaam (Standing) is one of the pillars of the prayer. So, the the prayer cannot be done without it; i.e. the prayer becomes invalid unless the person is not able to stand.

If a person is unable to stand, he may pray while sitting or even sometimes lying down if unable to sit.

As for the reason you mentioned, it is not sufficient to abandon standing in the prayer; above all, you said there was a place (garden) where you could pray as prescribed. You should go to that place or to any place where you could pray as Allah ordained you. Do not fear people or feel shy in front of them. On the contrary, show the rituals of your religion, which is the only true religion. Those pagans and polytheists do not fear showing their rites in public places although they are wrong and misled.

You should be proud of your religion and the ways of worship in Islam.

You must repent and know that the prayer is one of the pillars of Islam. Finally, you should make up all the prayers you have performed in the way you mentioned.

Allah knows best.