Who Was the First Muslim?

"And he (Jesus) went a little farther, and fell on his face, and prayed…" (Matthew 26:39)

"And Moses made haste, and bowed his head toward the earth, and worshiped." (Exodus 34:8)

Question: Who was the first believer? Moses or Muhammad? 7:143 says Moses was the first believer but 39:12 says Mohammad was the first believer.

References:
"And Moses fell down senseless. And when he woke he said: Glory unto Thee! I turn unto Thee repentant, and I am the first of the believers" (7:143).

"Say [O Muhammad], I am commanded to worship God and be devoted to His religion. And I am commanded that I shall be the first of those who submit" (39:11-12).

Answer: Can two firsts exist simultaneously? Yes, if points of both participants are equal, judges can declare both of the participants first and ask them to share the trophy. Can two firsts co-exist at different time periods? Yes, if Tom is Olympic champion this year, John can be Olympic champion next year.

Now let's answer the question. Moses was the first one among Jews to believe in Torah. Muhammad was the first one among Arabs to believe in Quran. 

God says-"God did choose Adam and Noah, the family of Abraham, and the family of 'Imran above all people. Descendants, some of them from others. And God is Hearing and Knowing" (3:33). 

A messenger of God who is appointed to a group of people is the first one among that group of people to believe in God's word.