Thank you very much for your question. It is our pleasure to answer it.

In the name of Allah, We praise Him, seek His help and ask for His forgiveness. Whoever Allah guides none can misguide, and whoever He allows to fall astray, none can guide them aright.

Dear brother, Allah says: 

"Verily, the prayer is enjoined on the believers at fixed hours". (An-Nisa' 4:103) 

Prayer offered before its time is not valid, according to the consensus of the Muslims. If a person offers a prayer before its time:

- If he does that deliberately, then the prayer is invalid and he is not free of sin.

- If that was not done deliberately, and he did it because he thought that the time for prayer had begun, then it is not a sin, and his prayer is regarded as nafl, but he has to repeat it because one of the conditions of the prayer is that it be done at the right time. 

However, if you mean offering prayer before the iqama, that is the second call to prayer, then it is permissible. You can offer prayer once te time of prayer starts. 

And Allah know best.