My understanding is God created earth & then put the animals on the earth sometime later.
Were dinosaurs on earth before God?
Dinosaurs lived on Earth, and - as religious people say - God made the Earth, so by that logic, Dinosaurs came after God. But all of that is irrelevant if you don't believe in God.
No. God created dinosaurs. Some dinosaurs (and pterosaurs) may indeed have been created in the fifth era listed in Genesis, when the Bible says that God made “flying creatures” and “great sea monsters.” Perhaps other types of dinosaurs were created in the sixth epoch. The vast array of dinosaurs with their huge appetites would have been appropriate considering the abundant vegetation that evidently existed in their time. (Genesis 1:20-24)
When the dinosaurs had fulfilled their purpose, God ended their life. But the Bible is silent on how he did that or when. We can be sure that dinosaurs were created by God for a purpose, even if we do not fully understand that purpose at this time.