right now I know that Bitcoin is a valuable asset from my understanding but other people doesn't accept the fact that it is really an asset,
They are not accepting because they don't know the value of it. And also add it to what you have said, bitcoin is not only an asset but also a currency. It is a digital currency exchange for goods and services, so don't tell someone that bitcoin is an asset alone but add the currency as well.
so I want to know a good wallet to use for my Bitcoin because I notice that some wallet my friends recommend to me are all exchange kind of wallet and I was told that it's not proper to use an exchange wallet for storing or saving of Bitcoin for a long time. I wish to have more recommendation or articles to read concerning wallets and it's security values but during my research I was recommended to use electrum wallet but I was confused if electrum wallet is an exchange or a custodial wallet, therefore i need a good direction, clarification and update of suitable wallet from senior colleagues.
There are different non custodian wallets which you can use to store your bitcoins. You can use either mobile app or desktop software. And the Electrum Wallet you mentioned is also a nice wallet to be used. So if you like it then you can go for it.