When you mint your NFT, there will be a brief waiting period as the transaction processes.
If you don't pay enough gas or if gas prices change on Ethereum right when you're minting the piece, the process will be slow. Every transaction that you execute from your wallet happens in sequential order—which means you must wait for each transaction to be completed before another one starts.
You can always check Etherscan by searching your wallet address (public key) to keep track of your latest transactions. If you cancel a mint, you’ll need to wait until it’s fully completed on the blockchain before minting again, otherwise you could potentially mint the piece twice.