Genesis 1:1 tells us that God first made the heavens and the earth, on the first day of creation.
ummm No it doesn't. It states the God made the heavens and the earth in the time period defined as the beginning and there is no reference anywhere that the terminology of the beginning is equivalent to a day. Here is a mechanical translation of Genesis 1:1 and 1:2
בְּרֵאשִׁית בָּרָּא אֱלֹהִׁים אֵת הַשָּמַיִׁם וְּאֵת הָּאָרֶץ
Gen1:1 in~ Summit he~ did~ Fatten “Elohiym [Powers]”
At the~ Sky~ s2 and~ At the~ Land
וְּהָּאָרֶץ הָּיְּתָּה תֹהוּ וָּבֹהוּ וְּחֹשֶךְ עַל פְּנֵי תְּהוֹם וְּרוּחַ אֱלֹהִׁים
מְּרַחֶפֶת עַל פְּנֵי הַמָּיִׁם
Gen1:2and~ the~ Land she~ had~ Exist Confusion
and~ Unfilled and~ Darkness Upon
Face~ s Deep.sea and~ Wind “Elohiym
[Powers]” much~ Flutter~ ing(fs) Upon
Face~ s the~ Water~ s2
Free pdf ----> http://www.ancient-hebrew.org/free/files/mtg.pdf
Besides the whole learning ancient Hebrew thing that everyone should pursue we have the plain translated words of Christ that assert that nothing was made that was made without the word and the question of the day for you here is what were the first words of God?