You don't have to worry about someone rejecting your comments or looking like a fool because no one knows who you are and where you live (unless you tell the person you are chatting with, which is a major no-no). Before too long, you will have made some new online friends.
If you are really concerned about your privacy being compromised (from trackers, websites, hackers, internet service providers etc), you can simply use a Virtual Private Network (VPN).
It may take a few seconds for the room to appear, but it shouldn't take more than a minute.
You can fill out a profile, but just put things that can't identify you outside the site. This site has many different rooms you can join in such as Singles, Flirt, Gay Les Bi, Advice, Party, Hottub, Zone, Christian, Seniors2008, Lounge, Military, Café, Dorm, Hangout, Lobby, Palace, and Park.
There are also a plethora of message boards if you don't prefer real-time chatting.
They allow you to find topics that interest you, then post your thoughts on them and read what other teens have to say.