I am a teacher and I offer the Zhuhr (Noon) Salah (Prayer) about ten minutes before the Adhan (call to prayer), meaning,
I perform Salah at 1:20 when the time of Zhuhr Salah is 1.30. This is because I go to the classroom before the Zhuhr prescribed time starts and stay there till the prescribed time of `Asr (Afternoon) Salah starts, which means that I miss both the optional and grace times of Zhuhr. Is my offering Zhuhr before its prescribed time valid?
If you perform Zhuhr Salah before its prescribed time starts, (Part No. 6; Page No. 122) your performance of Salah will be invalid and you will have to make up for the Salah you performed in this way. Moreover, you will have to repent and ask Allah (Exalted be He) for forgiveness. Furthermore, in the future, you should not embark on an act of worship unless you are certain that it is permissible.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.