Oxaloacetate forms together with acetyl-CoA citric acid. Now oxaloacetate is used but also re-used again in this cycle. But where does the first oxaloacetate comes from? Is that from the mother or produced by DNA or....?
There's not just one molecule of acetyl-CoA that's going through the TCA cycle. Every intermediate compound is present at a certain concentration, so there will be many oxaloacetate molecules per cell.
When the cell divides, it's split in two and the contents are also divided. So a new cell will also have many oxaloacetate molecules in it. This way the daughter cell can just keep running.
For the "first" oxaloacetate molecule we have to go back billions of years, and this would be a very complex question to answer. My guess would be that the first oxaloacetate molecule was produced by a non-TCA pathway, and the TCA cycle evolved later.