About Public key and private key, can hackers steal private key from public key? I am noob so please forgive me if my question is stupid.
What you need to worry about is phishing, malware, cloud account hack etc. The chances a hacker got your private key through those is way higher than trying to find private key through your public key.
If you have time to read, try to read "Mastering Bitcoin", it's a good book to start learning about Bitcoin.