At 6 Figure Drop Shipper, we encourage all students to find their own products and learn the valuable skill of being able to find winning products.
Now if you have found a product by yourself and you happen to find out at a later date that somebody else is selling it as well, then that is perfectly okay to sell as well.
Since you also found it yourself.
However, do not blatantly copy someone else just because their store is doing well.
This is harmful to yourself because if your store goes down overtime in sales, you would have not developed the skill of finding products.
Causing you to be further behind in the long run.