Coins will become mature when they are in your wallet for at least 24 hours.
When they are mature they will start staking.
Coins have been in the wallet for more than 24h probably it's the wallet that has never been opened for 24h, maybe that's the reason. Another question does the wifi signal effect staking? Should I attach the ethernet cable to my pc for better staking, my ping is 3ms and download speed is 70mbps
The speed of your internet connection doesn't affect the effectivity of staking. The only thing that matters is how much coins you have and their age.
And as others already said: The wallet does not need to run 24/7 to get stakes. Your weight is increasing even when your wallet is offline.