Should I have my battery replaced already? (iPhone 5/iOS7.0.3)?

Well umm I've been using my phone for like 5-6 hours to watch vids and chat to ppl on Facebook and for tweeting but mostly for chatting. My battery is at 20% now. Is this normal? Is it ios7 or my battery I'm kinda confused because I know that there are some complaints about ios7 battery life.

That's pretty normal. You don't have to worry about anything. Stop being so paranoid lol.