If everyone is giving free shipping for similar products, except for you, that might not be a good strategy. This is true, especially if you are dealing with commodity products.
If you are dealing with specialty products, you have your say. And the customers might be willing to pay extra for shipping.
You either deal with commodity products and follow the market rules or deal with specialty products and create your own rules.
The choice is yours, but the rules are different in what you choose.