|"that kind of helped but i just want to prove to my dad that port forwarding is not bad"|
Did you read everything? How about the pink box at the very top of the page?
"Before following these instructions please note that running server software on your computer without a clear understanding of what you are doing may seriously harm your system and lead to vulnerabilities. Do not open ports in your router without knowing exactly what you are doing."
And how about this?
"Since you're about to run your own server, you should be aware of the possible dangers. Although we can not prevent people from running their server and putting themselves at risk, we may at least appeal that you don't do it when having no idea what you actually do."
Have you done any research about this at all? I think the keywords in RED should be enough to show you that your dad is correct.